Apple or PC Does Apple have the market share it used to have

Apple or PC? Does Apple have the market share it used to have? Apple said that 35% of computer owners own an Apple computers. Has the percentage gone down? Out of 200 computer owners surveyed, 65 of them say they own an Apple computer. What is the p-value for this hypothesis test?

Solution

The test hypothesis:

Ho: p=0.35 (i.e. null hypothesis)

Ha: p<0.35 (i.e. alternative hypothesis)

The test statistic is

Z=(phat-p)/sqrt(p*(1-p)/n)

=(65/200-0.35)/sqrt(0.35*(1-0.35)/200)

=-0.74

It is a left-tailed test.

So the p-value= P(Z<-0.74) =0.2297 (from standard normal table)