Respuesta :
Explanation
In this problem, we have a population with a normal distribution with:
• mean μ = 85,
,• standard deviation σ = 24.
We must compute the z-score for different samples.
The standard deviation of a sample with mean M and size n is:
[tex]σ_M=\frac{σ}{\sqrt{n}}.[/tex]The z-score of the sample is given by:
[tex]z(M,n)=\frac{M-\mu}{\sigma_M}=\sqrt{n}\cdot(\frac{M-\mu}{\sigma})[/tex]Using these formulas, we compute the z-score of each sample:
(a) M = 91, n = 4
[tex]z(91,4)=\sqrt{4}\cdot(\frac{91-85}{24})=0.5.[/tex](b) M = 91, n = 9
[tex]z(91,9)=\sqrt{9}\cdot(\frac{91-85}{24})=0.75.[/tex](c) M = 91, n = 16
[tex]z(91,16)=\sqrt{16}\cdot(\frac{91-85}{24})=1.[/tex](d) M = 91, n = 36
[tex]z(91,9)=\sqrt{36}\cdot(\frac{91-85}{24})=1.5.[/tex]Answera. z = 0.5
b. z = 0.75
c. z = 1
d. z = 1.5
