Answer to Question #322871 in Statistics and Probability for sav

Question

2. Average Senior High School annual cost of tuition fee for all private schools last year

was Php43,700. A random sample of costs this year for 45 private schools indicated

that the sample mean was Php45,800 and a sample standard deviation was Php5,600.

At 0.01 level of significance, is there sufficient evidence to conclude that the cost

increased?

Answer 1

$\mu =43700$

n=45

$X=45800$

$\sigma=5600$

$Z=\frac{X-\mu}{\frac{\sigma}{\sqrt{n}}}=\frac{45800-43700}{\frac{5600}{\sqrt{45}}}=2.52$

$Z_{\lambda/2}=Z_{0.01/2}=Z_{0.005}=2.807$

$2.52<2.807$

There is no sufficient evidence to conclude that the cost has increased.