Two Different Types of Alloy, a and B, Have Been

Essay

Two different types of alloy, A and B, have been used to manufacture experimental specimens of a small tension link to be used in a certain engineering application. The ultimate strength (ksi) of each specimen was determined, and the results are summarized in the accompanying frequency distribution. $$\begin{array} { c c l } \hline & \text { A } & \text { B } \\\hline 26 - < 30 & 6 & 4 \\\hline 30 - < 34 & 12 & 9 \\\hline 34 - < 38 & 15 & 19 \\\hline 38 - < 42 & 7 & 10 \\\hline & m = 40 & n = 42 \\\hline\end{array}$$ Compute a 95% CI for the difference between the true proportions of all specimens of alloys A and B that have an ultimate strength of at least 34 ksi.