2.According to the archival data of a biology lab, 2-year old mice can solve a simple maze in 30 seconds on average, with a standard deviation of 2 seconds. In a recent experiment, a group of 25 2-year old mice were given the blood of younger mice to see if there is any improvement in terms of cognitive functions. These mice were observed to solve the same maze in 29 seconds. Can we say that the blood transfusion improved the cognitive functions of 2-year old mice (i.e. shorter time to solve the maze)? Assume that solving times are distributed normally.

a.State the hypotheses.

b.What is the p-value?

c. Using = .05, what is your conclusion?

3.Visitors of a webpage of a company spend 250 seconds per visit on average. In order to increase the time spent, the company redesigned the page. After the changes, a sample of 400 visitors were randomly selected. The sample mean was 260 and the sample standard deviation was 100. Based on this data can we say that the design change worked (using an alpha level of .05)?

Hint: Using Excel to find the p-value will be faster than using a t-table.

a.State the hypotheses.

b.What is the p-value?

c.Using = .05, what is your conclusion?