A Sample of 81 Women Aged $18 - 24$ Yields a Mean Systolic Blood Pressure Of

Multiple Choice

A sample of 81 women aged $18 - 24$ yields a mean systolic blood pressure of $114.6 \mathrm {~mm} \mathrm { Hg }$ . Assuming that $\sigma = 13.2 \mathrm {~mm} \mathrm { Hg }$ , find the margin of error in estimating $\mu$ at the $95 \%$ level of confidence.

A) $2.9 \mathrm {~mm} \mathrm { Hg }$
B) $43.7 \mathrm {~mm} \mathrm { Hg }$
C) $2.3 \mathrm {~mm} \mathrm { Hg }$
D) $2.8 \mathrm {~mm} \mathrm { Hg }$