=+11. Let  denote the true average reaction time to a certain stimulus. A test of H0:  5 5 versus Ha:  . 5 will be based on a large sample size so that when H0 is true, the test statistic z 5 (x 2 5)y(sy1n)

has approximately a standard normal distribution

(the z curve). Determine the value of z and the corresponding P-value in each of the following cases:

a. n 5 50, x 5 5.23, s 5 .89

b. n 5 35, x 5 5.72, s 5 1.01

c. n 5 40, x 5 5.35, s 5 1.67