Tonight's HW:
- Page 509-510: 17, 21
- For 17a show the full process--hypotheses, conditions, math, conclusion
- For 17b CALCULATE THE INTERVAL EVEN THOUGH YOU DID NOT HAVE EVIDENCE OF A DIFFERENCE
- you can just get the interval using your graphing calculator, copy your calculator screen, and then interpret this interval
- Consider the interval: how/why does your interval further support the idea that there "is not evidence of a decrease in voter support?"
- Answers not in the back:
- 17a.) Conditions: We know the first poll randomly selected voters; we'll assume the second poll used a random sample as well. Both 630 and 1010 are less than 10% of all voters in this state/town/district. (630)(.52)>10, (630)(1-0.52)>10, (1010)(0.52)>10, (1010)(1-.52)>10
- 17a.) Conclusion: The pvalue of 0.12 is above any common alpha level so we fail to reject the Ho. There is not evidence to suggest a decrease in voter support for his candidacy.
- 17b.) 99% Confidence Interval = (-0.0355, 0.09503)
- This interval does not suggest a significant difference (or a decrease) in voter support because the interval contains 0. If there was a decrease in support the entire interval would have been positive.
- 21a.) Conditions: We'll assume this is a representative sample of all women who never had mammograms and have had mammograms. 30,565 is likely less than <10 10="" 30131="" all="" had="" have="" is="" mammograms="" never="" of="" who="" women="">10% of all women who have never had mammograms and 30131 is likely less than 10% of all women who have had screening. (30565)(.006) > 10, (30565)(1-.006) > 10, (30131)(0.006) > 10, (30131)(1-.006) > 10
Another Stamp Opportunity (Stamps due next Thurs):
- You should have two leftover slides from our last chapter...one is about testing for ESP at Duke University and the other is about therapeutic touch.
- Stamp: Write the hypotheses for each scenario. Write the hypotheses on the slide (front or back).
- If you lost the slides you cannot earn these stamps.
Today's Class Recap:
- Stamp = 2 prop z interval MC
- HW Questions?
- Randomization condition for #7...
- Ch. 22 Notes:
- Conducting a 2 Proportion Z Test....
- Hypotheses (notes--some new stuff here)
- Conditions (one change happens as a result of our assumption in the null)
- Math (2 prop z test on calculator, copy screen)
- What is p-hat pooled? Why do we use it? Where do we use it?
- Conclusion (same old--use pvalue to reject or fail to reject, there is or is not evidence, copy context from question)
- Connecting 2 prop z intervals and tests...
- How can we use an interval to decide if there is a significant difference in two proportions?
Here's the plan leading up to our next test:
- We have one more chapter in this unit about inference for proportions....
- Ch. 22 = Inferences for Differences in Proportions (2 Prop Z Tests and 2 Prop Z Intervals)
Tuesday/Wednesday (3/19, 3/20): Ch. 20 Notes = 2 prop z-test and 2 prop z-int examples, notes- Thursday (3/21): Finish ch. 22 notes, one more test/interval example/context
- Friday (3/22): Ch. 22 classwork
- Monday (3/25): Start ch. 23 (T Tests and Intervals)
- Tuesday (3/26): TEST!
- Test will be...
- Matching vocab for the entire unit
- Some FR and MC (based more heavily on the 2 prop z stuff)
- Thurs (3/28) - Fri (3/29): The t distribution
- Monday (4/1): Another T Test/Interval Given Data
- Tuesday (4/2): Ch. 23 Practice
- Weds (4/3): Ch. 23 Quiz, Start Paired T Tests and Intervals (ch. 25)
- Thurs (4/4) - Fri (4/5): Paired T Tests and Intervals (ch. 25)
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