In order to determine whether or not there is a significant difference between the mean hourly wages paid by two companies (of the same industry), the following data have been accumulated. $$\begin{array} { l l l }
& \text { Company A } & \text { Company B } \
\text { Sample size } & 80 & 60 \
\text { Sample mean } & \$ 16.75 & \$ 16.25 \
\text { Population standard deviation } &\$ 1.00 & \$ .95
\end{array}$$ The test statistic is
A) .098.
B) 1.645.
C) 2.75.
D) 3.01.

Question

In order to determine whether or not there is a significant difference between the mean hourly wages paid by two companies (of the same industry), the following data have been accumulated. $$\begin{array} { l l l } 
 & \text { Company A } & \text { Company B } \
\text { Sample size } & 80 & 60 \
\text { Sample mean } & \$ 16.75 & \$ 16.25 \
\text { Population standard deviation } &\$ 1.00 & \$ .95
\end{array}$$   The test statistic is
A) .098.
B) 1.645.
C) 2.75.
D) 3.01.

Quizplus · Accepted Answer

The test statistic is calculated as follows:```z = (x̄1 - x̄2) / sqrt((σ1^2/n1) + (σ2^2/n2))```where:* x̄1 and x̄2 are the sample means* σ1 and σ2 are the population standard deviations* n1 and n2 are the sample sizesPlugging in the values from the question, we get:```z = (16.75 - 16.25) / sqrt((1.00^2/80) + (0.95^2/60))= 0.50 / sqrt(0.0125 + 0.0158)= 0.50 / sqrt(0.0283)= 0.50 / 0.168= 3.01```Therefore, the test statistic is 3.01, which corresponds to choice D.

In Order to Determine Whether or Not There Is a Significant