Answer: 15.08
Step-by-step explanation:
The test statistic for difference between two population means is given by :-
[tex]z=\dfrac{\overline{X}-\overline{Y}}{\sqrt{\dfrac{\sigma_x^2}{n_x}+\dfrac{\sigma_y^2}{n_y}}}[/tex]
Given : State A State B
Sample size 80 50
Mean interest rate (%) 4.0 4.5
Population variance 0.04 0.03
Then , the test statistic for difference between two population means will be :-
[tex]z=\dfrac{4.0-4.5}{\sqrt{\dfrac{0.04}{80}+\dfrac{0.03}{50}}}\\\\\Rightarrow z=15.0755672289\approx15.08[/tex]
Hence, the value of the test statistic will be 15.08 .