A consulting firm had predicted that 30% of employees at a large firm would take advantage of a new company Credit Union, but management is skeptical. They felt the rate would be lower. A survey of 250 employees show that 82 of them are currently taking advantage of the Credit Union. Calculate the appropriate test statistic based on this data.

Respuesta :

According to the data presented, the most convenient is to make an approximation through Z-Stadistic Proportions) For the sample size)

So things,

A)

[tex]H_0 = p=.30[/tex]

[tex]SE= \sqrt{\frac{p_0(1-p_0)}{n}} = \sqrt{\frac{0.30(1-0.30)}{250}} = 0.0289[/tex]

b) Given [tex]n=250[/tex] and [tex]x=82[/tex] so [tex]\hat{p} =[/tex]sample proportion [tex]= \frac{x}{n} = \frac{82}{250}=0.328[/tex]

[tex]z= \frac{\hat{p}-p_0}{\sqrt{\frac{p_0(1-p_0))}{n}}}=\frac{0.328-0.3}{0.0289}=0.96[/tex]

c)

So, A z-value less than 2 or more than 2 is considered unusually small and unusually large respectively,

Then, Since z=0.96<2, the z-test stadistic is unusually small.