A Statistics Teacher Started Class One Day by Drawing the Names

Multiple Choice

A statistics teacher started class one day by drawing the names of 10 students out of a hat and asked them to do as many pushups as they could. The 10 randomly selected students averaged 15 pushups per person with a standard deviation of 9 pushups. Suppose the distribution of the population of number of pushups that can be done is approximately normal. If we would like to capture the population mean with 95% confidence the margin of error would be ?

A) $1.960 \left( \frac { 9 } { \sqrt { 10 } } \right)$
B) $2.125 \left( \frac { 15 } { \sqrt { 10 } } \right)$
C) $2.262 \left( \frac { 9 } { \sqrt { 10 } } \right)$
D) $3.250 \left( \frac { 15 } { \sqrt { 10 } } \right)$