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.
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