The two samples whose statistics are given in the table thought to come from populations with
Equal variances. What is the pooled estimate of the population standard deviation? $$\begin{array} { | c | c | c | }
\hline \boldsymbol { n } & \text { Mean } & \text { SD } \
\hline 50 & 22 & 3 \
\hline 55 & 25 & 4 \
\hline
\end{array}$$
A) 3.52
B) 5.00
C) 3.56
D) 1.87
E) 3.50

Question

The two samples whose statistics are given in the table thought to come from populations with
Equal variances. What is the pooled estimate of the population standard deviation? $$\begin{array} { | c | c | c | } 
\hline \boldsymbol { n } & \text { Mean } & \text { SD } \
\hline 50 & 22 & 3 \
\hline 55 & 25 & 4 \
\hline
\end{array}$$
A) 3.52
B) 5.00
C) 3.56
D) 1.87
E) 3.50

Quizplus · Accepted Answer

The pooled standard deviation is calculated using the formula: $\sqrt{\frac{(n_1-1)s_1^2 + (n_2-1)s_2^2}{n_1+n_2-2}}$. Substituting the given values: $\sqrt{\frac{(50-1)3^2 + (55-1)4^2}{50+55-2}} = 3.56$.

The Two Samples Whose Statistics Are Given in the Table