An automatic coffee machine dispenses cups of coffee whose volume per cup varies normally with the mean = 10 oz. A quality-control researcher randomly selects 8 cups of coffee from the machine and finds that in this sample the mean volume is 9.92 oz. and the standard deviation is 0.23 oz.

We want to determine if these data provide enough evidence to conclude that the mean volume dispensed is less than 10 oz.

Which one of options below is a correct description of the appropriate methodology?

a.) One-sample t-test

b.) One-sample z-test

c.) Neither is appropriate