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Tuesday, March 31, 2015

2'sDay HW

Tonight, please complete the 2 proportion z test and 2 proportion z interval worksheet provided in class! (titled Chapter 22 Quiz B). 

Tomorrow we'll wrap up our notes on chapter 22, then do some practice tomorrow and Thursday!

HomeworK: Chapter 22 Quiz B
In 2000, the United Nations claimed that there was a higher rate of illiteracy in men than in women from the country of Qatar. A humanitarian organization went to Qatar to conduct a random sample. The results showed that 45 out of 234 men and 42 out of 251 women were classified as illiterate on the same measurement test.

1.       Do the samples above provide evidence that the United Nations’ claim was correct—that there was a higher illiteracy rate in men than in women (in Qatar)? Test an appropriate hypothesis and state your conclusion.


2.       Show the appropriate mathematics and calculate a 95% confidence interval for the difference in proportions of illiteracy in men and women from Qatar. Then, interpret your interval.

Monday, March 30, 2015

Monday...no homework! (PERIOD B: Don't worry about that conclusion!)

Today, take the night off. I think I may procrastinate on some school work tonight, so you guys can do the same. In other words...no homework tonight!

And remember, stamps are due tomorrow, Weds, or Thursday--but Thursday is the last day you can turn them in! Since there is no homework tonight, it's a great night to count these up!
  • Count up your stamps and record the total on the front 
  •  Double check your counting!
  •  Only papers with actual stamps on them count! This time I'll be paying extra attention for people who sneak papers without stamps in!

Tomorrow in class we'll finish up our 2 proportion z-test, then we'll talk about a 2 proportion z-interval. We'll wrap up with notes on Wednesday, then do some AP problems on Thursday for a quiz grade!


Friday, March 27, 2015

TAKE HOME TEST: MIDTERM REVIEW!

This weekend, please complete the Midterm Exam Review assignment provided/outlined in class! It's a take home test grade!
  • You need 4 things: your midterm exam, a copy of the assignment, a sheet with all of the multiple choice hints, and the free-response scoring rubric.
    • The assignment, multiple choice hints, and rubric can be found under our classroom resources link--feel free to use these to type up your answers if you like!
  • Your grade will be based entirely on effort (as judged by me :) )
  • Your task is to select 10 multiple choice questions that you answered incorrectly on the midterm, and then record notes/correct work for each question: what should/could you have done differently to get the correct answer?
  • Then, for the free response, do the same--use the scoring rubric to describe what you would need to add/do differently to earn an"E" on each question!
  • All of the directions are outlined in the assignment!
Good luck! End the third quarter with a 100% on a test grade!

Thursday, March 26, 2015

TEST TOMORROW!

Tomorrow is a big day, and this is a big weekend upcoming. This is your last chance to boost your grade with some great test scores!

Here's a breakdown of tomorrow's test:

  • 2 free response, 7 multiple choice, 5 true false
  • Describe Type I and/or Type II error and a consequence
  • Conduct a hypothesis test (hypotheses, conditions, math, conclusion)
  • Interpret p-value (in context)
  • Create a confidence interval (conditions, math, interpret)
  • Interpret the meaning of a confidence interval
  • Interpret the meaning of a confidence level
  • Find margin of error
  • Know how alpha and beta affect each other, and how changing alpha/beta affects power
  • Find sample size given margin of error
  • Find the confidence level associated with a given alpha level (use the table we created in our notes yesterday!)
  • Interpret margin of error
  • Know how changes in confidence level (z*) and sample size affect the margin of error and the width of an interval
  • Know how alpha and beta (probabilities of Type 1, Type 2 error) are affected by increasing sample size
  • Know how to calculate power
  • Study your (40 point) chapter 19 quiz and your hypothesis test quiz from earlier this week! 
  • Also, review your Type I/II error, alpha/beta/power notes (anything we covered this week)
Here are the answers to today's multiple choice questions in case you're using them to study!
  • True/False Worksheet
    1. False
    2. True
    3. False
    4. True
    5. True
    6. D
    7. (#15 about the mayor of a large city) E
    8. (Corn rootworm question) A
    9. (#10; when performing a test...) D+
  • AP Statistics Exam: Multiple Choice Section Worksheet
    • (A 95% confidenc interval of the form...) C
    • (USA Today reported that speed skater...) E
    • (Courtney has constructed a cricket out of paper...) D
    • (A survey was conducted to determine...) C
    • (A certain county has 1,000 farms...) A
    • (Suppose that public opinion in a large city...) D

Here's an extra credit homework assignment you can do--due Monday (do it on separate paper, not in your notebook)--if you like!
  • Page 491: 1, 3, 7, 17
And lastly, we know we have a MAJOR assignment this weekend, reviewing our midterm exam! Check back tomorrow for a blog post all about that (though we discussed it today in class)...






Wednesday, March 25, 2015

Wednesday!

Hump dayyyyyyyyy (and the last Wednesday of March!)

Tonight, please complete the following in your textbook:

Page 491: 9, 19, 21

This homework is a great opportunity to review for the test, as it covers a confidence interval (9), a hypothesis test and p-value (21), and types of error (19).

Here's an extra credit homework assignment you can do--due Friday--if you like!

Page 491: 1, 3, 7, 17

Tomorrow we'll finish up chapter 21, and then we have our TEST FRIDAY! Next week we'll have 4 days (Monday through Thursday) to learn 2 proportion z-tests and intervals before break! DON'T BE ABSENT!

Tuesday, March 24, 2015

Tuesday HW...

Tonight, please complete the "Chapter 21: Types of Error" worksheet provided in class! This gives you some practice with the type of questions you'll see on Friday's test (about types of error)!

  • For 1B, your task is to figure out the confidence level based on our alpha level--we'll get into this some more tomorrow! For now, do your best! Or, check p. 479-480 about critical values!
  • For 2d and 2e, you are asked how the power and risks of Type I/II error are affected--use the flow chart I provided in class!
    • Also, know that as we increase alpha, beta decreases!
  • For 3cd, remember that alpha is the probability of a type 1 error and beta is the probability of a type 2 error...
    • These probabilities are given: try to remember, false + is which type? false -? 
    • Remember, power = 1 - beta.
Here are the homework questions in case you don't have a copy:


Chapter 21: Types of Error
1.)    In attempt to increase the percentage of people wearing seat belts, Massachusetts instituted a “click-it or ticket” policy. Use of safety belts rose to 62% in 2003, with a goal of surpassing 80% by 2005. That year (in 2005), of 134 stopped drivers, 23 were not wearing their seatbelt. Does this provide evidence of meeting the goal? If we have met the goal, Massachusetts will cut back funding on the “click-it or ticket” program.
a.      Define each type of error and a consequence of each.
b.      If we use an alpha level of 0.05, what is the associated confidence level?
           
2.)    A company is willing to renew its advertising contract with a local radio station only if the station can prove that more than 20% of the residents of the city have heard the ad and recognize the company’s product. The radio station conducts a random phone survey of 400 people.
a.      Write the hypotheses.
b.      Define a Type I error and identify a potential consequence.
c.       Define a Type 2 error and identify a potential consequence.
d.      Which alpha level--.01, .05, or .10—will maximize the power of this test?
e.      The company proposes the station call 600 people rather than 400. How will this affect the power? Will this make the risk of a Type I/Type II higher or lower?

3.)    Testing for Alzheimer’s disease can be a long and expensive process, consisting of lengthy tests and medical diagnosis. Recently, a group of researchers devised a 7 minute test to serve as a quick screen for the disease for use in the general population of senior citizens. A patient who tested positive would then go through the more expensive battery of tests and medical diagnosis. The authors reported a false positive rate of 4% and a false negative rate of 8%.
a.      Define a Type I error and identify a potential consequence.
b.      Define a Type 2 error and identify a potential consequence.
c.       What is the alpha level?
d.      Calculate the power of this test? 



Homework Answer Key (will be provided in class tomorrow):




Monday, March 23, 2015

Monday HW....YOU CAN'T DO THE 2012 AP PROBLEM! My bad!

Tonight, please complete ONLY the 2010 #3 AP problem....and study for tomorrow's quiz!

  • I made a mistake! The 2012 problem is a 2 proportion z-test, so we can't do it yet! We'll save it for our notes next week!

  • Check your answers to prepare yourself for tomorrow's quiz!
  • 2010 Answer Key/Scoring Rubric
  • Study 9, 17, 19 and 21 from our book homework for tomorrow!

A few other things to keep in mind...
  • Mandatory MEETING next WEDNESDAY (4/1) for all AP students after school!
  • We have a TEST on chapters 19-21 FRIDAY!
  • STAMPS are due NEXT WEEK!


Friday, March 20, 2015

Weekend and Monday Homework and Vocab (I didn't mess this post up)

Ok...so...this is the real post....periods B and E I changed my mind about your homework...

Here's you homework for the weekend/Monday:

  • Weekend Homework:
    • Finish p. 470: 9, 17, 19, 21 (if you didn't already--I'm checking these Monday)
    • Study your vocab!
  • Monday Homework:
    • Complete the two AP problems (2010#3 and 2012#4) that I gave you in class today\
    • Study for Tuesday's "math" quiz
  • So, feel free to do the AP problems this weekend (along with studying your vocab) if you don't want to do them Monday night!
And here's a vocab list for Monday. All of the words from our chapter 19 quiz will be on Monday's vocab quiz. (ch. 19 words on page 444, ch. 20 words on page 468)
  • Meaning of __% Confidence
  • Standard Error
  • Critical Value (z*)
  • Margin of Error
  • Confidence Interval
  • Hypothesis Test
  • Null Hypothesis
  • Alternative Hypothesis
  • One Sided/Tailed Test
  • Two Sided/Tailed Test
  • Alpha/Significance Level (on p. 489)
  • P-Value
  • When do we reject the null? (compare p-value and alpha)
  • When do we fail to reject the null? (compare p-value to alpha)


Thursday, March 19, 2015

Thursssdayyyyy.....

Tonight, please complete the following in your textbook:

Page 470: 9, 17, 19, 21

  • For 17, 19, 21 you need to do the entire hypothesis test process! (Hypotheses, Conditions, Math, Conclusion)
  • None of the three problems provides an alpha/significance level for your conclusion: pick one! (5%?)
  • This homework is the same thing you'll have to do on our chapter 20 quiz next week!
  • Use the writing template from class (or below) to help you with your conclusion!
    • Since the p-value of (p-value) is lower/higher than the (alpha level)% significance/alpha level, we will reject/fail to reject the null hypothesis. There is/is not significant evidence to conclude (interpret the alternative hypothesis in context) based on the given sample.
E



Tuesday, March 17, 2015

Tuesday/Wednesday HW (Period E,F)

Periods E,F: Tonight (for homework), please show the hypotheses, conditions, and math for the remaining 2 problems on our classwork handout (news from the internet and vouchers). This will be checked on Thursday.

Period B: No homework! 

Tomorrow (in class) we'll discuss the conclusions for a hypothesis test...then, on Friday, we'll do some practice, more practice Monday, and then we'll start chapter 21 Tuesday!

See you there!

In case you lost them, on Thursday you should have the hypotheses, conditions, and math for each of the scenarios below.


1.)    In May of 2000 the Pew Research Foundation sampled 1593 respondents and asked how they obtain news. The foundation reports that 33% now say they obtain news from the Internet at least once a week. It has generally been assumed, based on earlier polls, that only 25% of people obtain news from the Internet. Does the Pew result provide strong evidence that this percentage has changed? Show appropriate statistical support to test this hypothesis.

2.)    Some boxes of a certain brand of breakfast cereal include a voucher for a free video rental inside the box. The company that makes the cereal claims that a voucher can be found in 20% of the boxes. However, based on their experiences eating the cereal at home, a group of students believes that the proportion of boxes with vouchers is less than 0.2. This group of students purchased 65 boxes of the cereal to investigate the company’s claim. The students found a total of 11 vouchers for free video rentals in the 65 boxes.

Suppose it is reasonable to assume that the 65 boxes purchased by the students are a random sample of all boxes of this cereal. Based on this sample, is there support for the students’ belief that the proportion of boxes with vouchers is less than 0.2? Provide statistical evidence to support your answer.


3.)    Pepsi did a study that showed 63% of Americans preferred Pepsi over Coke. You decide to go to the mall and have a taste test. You randomly select 165 shoppers and 93 said they prefer Pepsi over Coke. Decide if your results differed from Pepsi’s results at a 10% significance level. 


Monday, March 16, 2015

Monday HW

Tonight, please complete the following in your textbook:

Page 469: 1, 2, 15

A few other things to keep in mind...

  • Tomorrow we are going to continue our notes on hypothesis testing, and we will focus mostly on the "math" and "conclusion." If you're going to the Boston Science Museum--have a great time! Butttt....also make sure you get the notes! You're responsible for what you missed!
    • If you are free, come to my class period B on Wednesday to learn what you missed
  • CAPT seminars are Wednesday! Be here!


Friday, March 13, 2015

Tomorrow is the Most Epic Pi Day Ever!

Not only is tomorrow Albert Einstein's birthday, it's the most epic pi day ever: 3/14/15 @ 9:26 and 53 seconds = 3.141592653!

To celebrate....how about some Stats homework?! :)

This weekend, please complete the chapter 20 reading questions provided in class (or below).

In addition, feel free to try out the extra credit homework I provided in class (or below).

  • For each scenario, show the conditions, math, and interpret the interval!
Enjoy! See you all Monday! Be here!

Chapter 20 Reading Questions:


1.)    What is a p-value? (p. 452 and 457)
2.)    For a hypothesis test we write two hypothesis, one of which is the null hypothesis; how do we denote the null hypothesis and what is it? (p. 453 and 456)
3.)    Read the sections A Trial as a Hypothesis Test and What to Do with an “Innocent” Defendant. In the space below, outline this analogy to describe a hypothesis test (use bullet points). (p. 454-455).
4.)    A hypothesis test is a four step process. First, we must write our hypotheses, the null and the alternative hypothesis. Describe the alternative hypothesis. (p. 456)
5.)    What is the name of this test? (p. 457)
6.)    What is a two-sided alternative? A one-sided alternative? (p. 458)
7.)    Examine the “Step-by-Step” example on page 459-460 (or p. 463-464). Testing a hypothesis is a four step process. Describe, in your own words, the four step process for a hypothesis test. (Skip the “Plan” heading in blue; headings for the 4 steps follow in blue, starting with “Hypotheses.”).
8.)    Look at the yellow “TI Tips” box on page 461. What test are we going to use in our graphing calculator? We will have to enter 3 numbers in the calculator: what are these 3 numbers that we’ll have to enter?  

Extra Credit Homework: Show conditions, math, interpret the interval for 1,2

A survey of approximately 4,200 high school students in the Midwest (at a meeting of the American Public Health Association in Denver) showed that 19.8% of students were “hypertexters” and 11.5% were “hypernetworkers.” “Hypertexting” is defined as sending at least 120 messages per school day. While “hypernetworking” is defined as spending at least 3 hours per school day on social networking sites.
1.       Create a 90% confidence interval for the proportion of Midwest high school students who can be categorized as “hypertexters.”
2.       Create a 99% confidence interval to estimate the percent of Midwest high-school students who “hypernetwork.” 


Thursday, March 12, 2015

Chapter 19 Quiz Tomorrow!

Tonight, study! Tomorrow's quiz is worth the most points of any quiz this quarter (40)! Our other quizzes maxed out around 20 points!

  • Determine if we can use a one proportion z-interval (conditions)
  • Create the interval (math!)
  • Interpret a confidence interval
  • Know how changing confidence affects the ME and width of the interval
  • Know how changing sample size affects the ME and width of the interval
  • Find sample size
  • Calculate margin of error
  • Interpret confidence level
  • Use your interval to justify a claim
  • Find p-hat and ME given just the interval
  • Vocab
    • Check the list/definitions from yesterday's post!
Good luck! See you tomorrow!

Wednesday, March 11, 2015

Wednesday

Good morning! I'm sorry I didn't make it in today...just not feeling 100%. I'll be back tomorrow for some more confidence intervals before our chapter 19 quiz on Friday. As much as I hate being out of school, I do like the fact that it gives you all a little more experience working on some AP multiple choice without being able to ask questions--like on the AP Exam (May 13th!)

Tonight, please complete the confidence intervals worksheet provided in class! I should have all of today's classwork graded and back to you tomorrow (thank Ms. Paige for picking it up for me)!

Friday's quiz will also include vocabulary. Here's a list if you want to get a head start studying:

  • Confidence Interval: a tool we use to estimate the value of a population parameter (using sample data)
  • One Proportion Z Interval: an interval used to estimate a population %/proportion (p); based on 1 sample of categorical data
  • Margin of Error: the extent of the interval on either side of our statistic (p-hat); (make sure you know how it's calculated also!)
  • Critical Value: z*; the number of standard errors (deviations) from the mean for a given confidence level
  • 10% Condition: sample has to be less than 10% of the population
  • Randomization: we want our sample to be collected at random (so it's representative); if not, proceed with caution
  • Success/Failure: (n)(p-hat)>10 and (n)(q-hat)>10
  • p: the %/proportion of the population (population parameter)
  • p-hat: the %/proportion calculated from our sample (sample statistic)
Hopefully you all aced your assignments today! See you manana!

Tuesday, March 10, 2015

2sDay HW

Tonight, please complete the following in your textbook: 

Page 447: 7, 11, 13c, 33, 35

Tomorrow we'll spend our period doing some classwork practice...Thursday (half-day) we'll answer any lingering questions and such, and then we'll have a chapter 19 quiz on Friday! Be ready!

Monday, March 9, 2015

Monday HW!

Tonight, please complete the "Classwork Examples" worksheet that we started in class (or you can find it below.)

A few comments on your homework...

  • Remember, 2 and 3 both ask us to "estimate the percentage..." This means we need to create a confidence interval and do the 3 step process: Conditions, Math, Interpret the Interval
  • Numbers 4 and 5 use an idea we have not discussed in class-finding sample size.
    • First, think: what part of the confidence interval formula represents margin of error?
    • Once you've figured that out, we want to set the ME = 0.05.
      • So, set the margin of error part of the formula equal to 0.05\
      • Substitute in z*, p-hat, and q-hat
      • Then, do some algebra to solve for n
        • Divide by z* on both sides
        • Square both sides
        • Multiply p-hat and q-hat to rewrite the numerator
        • Cross multiply
      • OR, check out the example on page 442, "Choosing Your Sample Size."
Enjoy! See you manana!


Classwork Examples: (Tonight's Homework)
1.)    In June 2004 Gallup/CNN/USA Today asked 909 registered voters if there was “Some chance they could vote for other candidates” beside their first choice. Only 18% indicated a chance they may switch votes. The resulting 95% confidence interval is shown below:
a.       Show the work!

b.      What do we enter in our graphing calculator to get this interval?

 Based on your interval (above), which statements below are correct? Incorrect?
a.       In the sample of 909 registered voters, somewhere between 15.5% and 20.5% of them said there is a chance they might switch votes.
b.      We’re 95% confident that 18% of all U.S. registered voters had some chance of switching votes.
c.       We’re 95% confident that between 15.5% and 20.5% of all U.S. registered voters had some chance of switching votes.
d.      We know that between 15.5% and 20.5% of all U.S. registered voters had some chance of switching votes.
e.      95% of all U.S. registered voters had some chance of switching votes.
2.)    College grads are more satisfied with their jobs: College-educated Millennials are more likely to see themselves on a career path, rather than just working at a job to get them by. This is based on a Pew Research Center poll of 2,002 employed 25-32 year old Americans. In the sample, 53% of employees say they are “very satisfied” with their current job.

a.       Estimate the percentage of all employed 25-32 year old Americans with a bachelor’s degree who are “very satisfied” with their current job.

b.      If we wanted to be 98% confident, would our confidence interval need to be wider or narrower?
c.       Our margin of error was about 4%. If we wanted to reduce it to 3%, would our level of confidence be higher or lower?
d.      If the Pew organization had polled more people, would the interval’s margin of error have been larger or smaller?

3.)    Estimate the proportion of Americans who are or who have been employed who say the sex of their coworkers doesn’t matter. (p-hat = 0.77; n = 1,963)

4.)    It used to be more common for a husband to have more education than his wife in America. But now, for the first time since Pew Research has tracked this trend over the past 50 years, the share of couples in which the wife is the one “marrying down” educationally is higher than those in which the husband has more education.

Among married women in 2012, 21% had spouses who were less educated than they were—a threefold increase from 1960, according to a new Pew Research Center analysis of Census data.

How many people would we have to survey to estimate the proportion of men who “married down” within 5%?

5.)    Let’s say we want a 3% margin of error with 95% confidence…we’re polling voter support (2 candidates, each equally likely). How many voters should we sample?

Friday, March 6, 2015

The Wknd!

This weekend, please complete the following in your textbook:

Page 447: 13abd, 17, 21ab, 23abc

  • We have not discussed what "95% confidence" (or any other % confidence) means yet, so those are the parts you're skipping on your homework
  • Remember, if you're asked to create an interval, show the mathematical formula with the correct #'s substituted, and then use your calculator to create the interval

Also, don't forget we have a quiz on Monday about the conditions, sample, population, x, n, and p-hat (look at Friday's stamp)!

Enjoy your weekend! More confidence interval stuff for the majority of next week! See you there!


Thursday, March 5, 2015

Thursday HW!

Tonight, please complete the following in your textbook:

Page 446: 3, 9

  • For #3, you need to identify the sample, population, p-hat, and check the conditions for each scenario (a,b,c,d). That means this question will take up a lot of space! You have do all of this to get hw credit! This is also practice for our first quiz!
  • For #9, you want to interpret the interval given; use the same writing template from #4 of today's investigation
  • This homework is practice for our upcoming pop quiz! (tomorrow?)
Tomorrow we will continue to investigate and learn about confidence intervals! See you there!

Wednesday, March 4, 2015

Last Sampling Distribution HW!

Tonight, please complete the 2010 AP Free Response and the 4 multiple choice on the back! A few hints...

  • To "describe the sampling distribution" in part A you need to check the conditions and then define the shape, mean, and standard deviation.
    • I would recommend sketching the Normal model and labeling the mean, then showing the standard deviation formula!
  • For b, think: if we have 160 minutes for 40 songs, what is the average song length? So, to find the probability that we exceed the available airtime, that's the same as finding the probability that the average song length is over ____ minutes
  • Multiple choice #14 has nothing to do with sampling distributions! This is some probability review!
  • Here is a link to the AP Free Response answers/rubric: 2010 #2 Scoring Rubric and Answer Key

Tomorrow we'll get into some confidence intervals! I CAN'T WAIT! See you there!





Tuesday, March 3, 2015

Tuesday HW....

You have two things to take care of tonight:

1.) Complete the sampling distribution classwork that we started (in class) today! You can also find this worksheet below. Remember, this will be collected and graded as classwork, so make sure you get it done!

2.) Study for your ch. 18 vocab quiz!

Here's a list of what to know for our chapter 18 vocab quiz:

  • Sampling Variability
  • Standard Error
  • Central Limit Theorem
  • Sampling Distribution
  • 10% Condition
  • "Large Enough Sample" condition
  • Know how increasing n affects the standard deviation
  • A sampling distribution for means is used with quantitative data
  • A sampling distribution for proportions is used with categorical data
  • Know which 3 conditions to check for each type of sampling distribution
  • Remember, sampling distribution questions are about the "mean of a sample" or the "proportion/% of a sample"

Enjoy! If we end up with a snow day tomorrow (I think we'll be in school), you'll have this quiz/hw due Thursday! Be ready!

Monday, March 2, 2015

Monday HW

Tonight, please complete the following in your textbook:

Page 428: 9, 15, 25abd, 35

Tomorrow in class we'll do some groupwork to practice sampling distributions more. Then, on Wednesday we'll have our chapter 18 vocab quiz and finish up some chapter 18 notes (some more details). Thursday we're on to confidence intervals! Woooo!

Enjoy your Monday afternoon! Go outside and play!


Sunday, March 1, 2015

Interesting Article...

I thought this was interesting...check it out! (If you're looking for your homework, check the post below!)

http://www.pewresearch.org/fact-tank/2014/02/11/6-key-findings-about-going-to-college/