91Ó°ÊÓ

Population mean $\left(\mathrm{μ}\right)=100$.

Population standard deviation $\left(\mathrm{σ}\right)=15$.

Sample size $\left(n\right)=60$.

The probability that selected individuals' WAIS scores are $105$ or higher can be computed as follows:

$P(x>29)=P\left(Z>\frac{105-100}{15}\right)$

$=0.3707$

Population mean $\left(\mathrm{μ}\right)=100$.

Population standard deviation $\left(\mathrm{σ}\right)=15$.

Sample size $\left(n\right)=60$.

Calculate the mean and standard deviation as follows:

${\mathrm{μ}}_{\stackrel{¯}{x}}=\mathrm{μ}$

$\mathrm{μ}=100$

${\mathrm{σ}}_{\stackrel{¯}{x}}=\frac{\mathrm{σ}}{\sqrt{n}}$

$=\frac{15}{\sqrt{60}}$

$=1.937$

Population mean $\left(\mathrm{μ}\right)=100$.

Population standard deviation $\left(\mathrm{σ}\right)=15$.

Sample size $\left(n\right)=60$.

The probability that the average WAIS score is $105$or higher can be estimated as follows:

$P(\stackrel{¯}{x}>105)=P\left(Z>\frac{105-100}{\frac{15}{\sqrt{60}}}\right)$

$=P(Z>2.58)$

$=0.0049$

Population mean $\left(\mathrm{μ}\right)=100$.

Population standard deviation $\left(\mathrm{σ}\right)=15$.

Sample size $\left(n\right)=60$.

If the distribution is said to be non-normal, (a) will be influenced.

However, because the sample size is more than $30$, the answers of (b) and (c) would be unaffected.