The following data are the response times in seconds for n = 25 first graders to arrange three objects by size.

a. Find the mean and the standard deviation for these 25 response times.
b. Order the data from smallest to largest.
c. Find the z-scores for the smallest and largest response times. Is there any reason to believe that these times are unusually large or small? Explain.

5.2 3.8 5.7 3.9 3.7 4.2 4.1 4.3 4.7 4.3 3.1 2.5 3.0 4.4 4.8 3.6 3.9 4.8 5.3 4.2 4.7 3.3 4.2 3.8 5.4