91影视

Let ${渭}_1$be the mean years of experience for commercial suppliers and ${渭}_2$be the mean years of experience for government employees.

The hypothesis that the company would like to test will be:

Null hypothesis: $H_0:{渭}_1={渭}_2$. That is, the mean years of experience for commercial suppliers is not less than the mean years of experience for government employees.

Alternate hypothesis: $H_0:{渭}_1<{渭}_2$. That is, the mean years of experience for commercial suppliers are less than the mean years of experience for government employees.

It is given that,

The level of significance 5% is0.05 .

$$\begin{gathered} n_1=6,n_2=11 \\ {\stackrel{炉}{x}}_1=12.33,{\stackrel{炉}{x}}_2=20.82 \\ Z=\frac{\left({\stackrel{炉}{x}}_1-{\stackrel{炉}{x}}_2\right)-\left({渭}_1-{渭}_2\right)}{\sqrt{\frac{{{蟽}_1}^2}{n}+\frac{{{蟽}_2}^2}{n}}} \\ =\frac{\left(12.33-20.82\right)-0}{\sqrt{\frac{{\left(8.10\right)}^2}{6}+\frac{{\left(8.93\right)}^2}{11}}} \\ =\frac{-8.49}{4.26} \\ =-1.993 \end{gathered}$$

So, the p-value is .046.

As the p-value is less than the significance level, so the null hypothesis will be rejected. Therefore, it can be concluded that the mean years of experience for commercial suppliers is less than the mean years of experience for government employees.

The assumptions are:

• Each sample is taken from simple random sampling.
• Each sample is independent.
• Each sample size is small.
• Each sample is approximately normally distributed.
• The population variance of the two samples is equal.