Random Samples Were Selected from Three Populations A Compute the Overall Mean

Essay

Random samples were selected from three populations. The data obtained are shown below. Please note that the sample sizes are not equal.
$\begin{array}{lll}\text { Treatment } 1&\text { Treatment } 2&\text { Treatment } 3\\45 & 31 & 39 \\41 & 34 & 35 \\37 & 35 & 40 \\40 & 40 & \\42 & &\end{array}$
a. Compute the overall mean .
b. At 95% confidence, test to see if there is a significant difference among the means.