Problem: The FDA ruled in the spring of 2013 that the emergency contraception "morning after" pill (Plan B) must now be available over the counter. Following that ruling, SurveyUSA polled a random sample of 500 Los Angeles adults, asking them if they agree with the FDA’s decision. The sample had 252 women and 248 men. 99 women and 122 men agree to the rule. Is there evidence that women and men in Los Angeles differed significantly in their opinions about the ruling?

Problem: The central tail feathers of the longtailed finch ( Poephila acuticauda ) are a sexually dimorphic trait hypothesized to play a role in sexual selection. The longer tail feathers in males cost energy to produce, and this is thought to serve as a token of the male’s excellent health condition. Here are the lengths of the central tail feathers (average of the two central feathers, in millimeters) of 19 male and 19 female longtailed finches:

1. Perform a hypothesis test for whether males’ central tail feather is significantly longer than the females’.
2. How much longer, on average, are the central tail feathers of male longtail finches than those of the females? Give a 95% confidence interval for the difference in population mean length between the male and the female adult longtail finches.

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Solution: The downloadable solution consists of 12 pages, 687 words and 7 charts.
Deliverable: Word Document