How Many Tissues Should a Package of Tissues Contain? Researchers $\bar { x } = 31 , s = 18$

Multiple Choice

How many tissues should a package of tissues contain? Researchers have determined that a person uses an average of 40 tissues during a cold. Suppose a random sample of 10,000 people yielded the following data on the number of tissues used during a cold: $\bar { x } = 31 , s = 18$ using the sample information provided, set up the calculation for the test statistic for the relevant hypothesis test, but do not simplify.

A) $z = \frac { 31 - 40 } { \frac { 18 } { \sqrt { 10,000 } } }$

B) $z = \frac { 31 - 40 } { \frac { 18 } { 10,000 ^ { 2 } } }$

C) $z = \frac { 31 - 40 } { 18 }$

D) $z = \frac { 31 - 40 } { \frac { 18 ^ { 2 } } { 10,000 } }$