Answer: -2.10
Step-by-step explanation:
Given : [tex]H_0:\mu=15[/tex]
[tex]H_a:\mu\neq15[/tex]
Sample size : n= 50, since the sample size is greater than 30 , so we apply z-test.
Sample mean : [tex]\overline{x}=14.11[/tex]
Standard deviation : [tex]\sigma= 3[/tex]
The test statistic for population mean :-
[tex]z=\dfrac{\overline{x}-\mu}{\dfrac{\sigma}{\sqrt{n}}}[/tex]
i.e. [tex]z=\dfrac{14.11-15}{\dfrac{3}{\sqrt{50}}}=-2.09775011752\approx-2.10[/tex]
Hence, the value of the test statistic = -2.10
