The phrase "You dirty rat" does rats a disservice. In a recent study, rats showed compassion that surprised scientists. Twenty-three of the thirty rats in the study freed another trapped rat in their cage, even when chocolate served as a distraction and even when the rats would then have to share the chocolate with their freed companion. (Rats, it turns out, love chocolate.) Rats did not open the cage when it was empty or when there was a stuffed animal inside, only when a fellow rat was trapped. We wish to use the sample to estimate the proportion of rats that would show empathy in this way. (Based on 3.88 from the book)

a. Give the relevant parameter and its best estimate.

Proportion

b. Use StatKey to create a bootstrap distribution with 1000 bootstrap samples. What is the shape of this distribution? What is the center of this distribution? What is the spread (standard error) of this distribution?

c. Use the standard error to find and interpret a 95% confidence interval for the proportion of rats likely to show empathy. Be sure to interpret the confidence interval within the context of the question!