A researcher is interested in whether giving rats a particular diet will have an effect on how fast they run a maze. Accordingly, 20 randomly selected subjects are given the experimental diet, and this group is subsequently found to have a mean run time of 130 seconds. If it is known that the mean of the population of rats without the special diet is 125 seconds and the standard deviation of the population is 10.5 seconds? Use = .05. What is the value of z for these data