Wednesday HW!

**AP FORMS AND FEES ARE DUE NEXT WEDNESDAY! GET THOSE IN!**

**I AM MISSING 2 YELLOW CALCULATORS; THEREFORE, NO STUDENTS WILL BE ALLOWED TO USE A CLASSROOM CALCULATOR UNTIL THESE ARE RETURNED. IF YOU DO NOT HAVE YOUR OWN CALCULATOR WHEN YOU COME TO CLASS AND CANNOT COMPLETE AN ASSIGNMENT YOU WILL EARN A 0, AS HAVING A CALCULATOR WAS AN EXPECTATION ON DAY 1. WHEN THESE ARE RETURNED I WILL CONSIDER RE-OPENING THE CLOSET.

(I trust you guys and know you're not thieves...maybe you took it by accident...just bring them back please.)


Tonight please complete the "AP Stat Stamp" problem provided in class (or below) about the proportion of females in the workforce

• For part (a) be sure to do each step of the confidence interval process (you should know from reading this question that it requires an interval)
• Condtions
• Math
• Interpret
• You can choose your confidence level (90%, 95%, 98%, 99%)
• Then, answer part (b) using this interval

WHY do we have this assignment for homework?

• Yes, I know that we've done lots of confidence interval practice and had a quiz on this today...
• This is not just busy work.
• We have this homework because this is an example of how we can use a confidence interval to test a hypothesis...
• Tomorrow and Friday we will explore how we could answer this question (b) in another way--using a hypothesis test!
• This example allows us to see the connection between hypothesis tests and confidence intervals--it shows how we can use a confidence interval to test a claim, and then we'll learn how to use a hypothesis test to do the same!
• I'm a poet and I didn't even know it.

Here is the homework question in case you lost yours or were absent (you can do this even if you were out! Be responsible!)

And here is a homework answer key so you can check your work:

• a.) Conditions: This was a random sample of 525 employment records; 525 < 10% of all employees in the U.S. labor force. (525)(0.436)>10 and (525)(0.564) > 10 (*Or, 229 > 10 and 296 > 10*). 
• A one proportion z-interval is appropriate.
• a.) Math:
• 0.436 +/- z*sqrt(0.436 x 0.564 / 525)
• The value of z* will vary depending on the confidence level chosen
• 90% Confidence Interval = (0.40059, 0.47179)
• 95% CI = (0.39377, 0.47861)
• 98% CI = (0.38584, 0.48654)
• 99% CI = (0.38044, 0.49194)
• a.) Interpret
• We are __% confident that the true percentage of females in the U.S. labor force falls between ___% and ___% based on this sample of 525 employment records.
• b.) Use our interval to test a claim:
• *No matter which confidence level you chose 46% falls within the interval...
• Reword the question for your context!
• The reps from the Dep't of Labor SHOULD NOT conclude that the percentage of females in the labor force is lower than Europe's rate of 46% because 46% falls within our __% confidence interval.
• OR...
• The reps from the Dep't of Labor SHOULD NOT conclude that the percentage of females in the labor force is lower than Europe's rate of 46% because our entire interval is not below 46%. 

Tomorrow in class we'll start to explore hypothesis tests, covered in chapters 20 and 21! See you there!