the shelf life of a carbonated beverage is of interest. ten bottles are randomly selected and tested. the following results are observed in days 108 124 124 106 115 138 163 159 134 139 We want to test if the true mean shelf life is greater than 125 days. which of the following is the test statistic?

a. Z = 0.31

b. Z = 0.97

c. Z = 3.07

d. Z = 0.9