Answer:
The test statistic (z-score) of this one-mean hypothesis test is z=1.823.
Explanation:
The null and alternative hypothesis are:
![H_0: \mu=150\\\\H_a: \mu\\eq 150](https://img.qammunity.org/2021/formulas/mathematics/college/vi73jp6utufg9vmb74fm41wzk6uwr3vteo.png)
The significance level is 0.05.
The sample size is n=22.
The sample mean is M=157.
The standard deviation is 18.
The z-score can be calculated as:
![z=(M-\mu)/(\sigma/√(n))=(157-150)/(18/√(22)) =(7)/(3.84) =1.823](https://img.qammunity.org/2021/formulas/mathematics/college/ltqqgwmpgfqvqd69x037d4jlxc2bu0oows.png)
The test statistic (z-score) of this one-mean hypothesis test is z=1.823.