Question

A survey of 2,254 American adults indicates that 17% of cell phone owners browse the internet exclusively on their phone rather than a computer or other device.50 (a) According to an online article, a report from a mobile research company indicates that 38 percent of Chinese mobile web users only access the internet through their cell phones.51 Conduct a hypothesis test to determine if these data provide strong evidence that the proportion of Americans who only use their cell phones to access the internet is different than the Chinese proportion of 38%.

Answer 1

Answer:

We conclude that the proportion of Americans who only use their cell phones to access the internet is different than the Chinese proportion of 38%.

Step-by-step explanation:

We are given that a survey of 2,254 American adults indicates that 17% of cell phone owners browse the internet exclusively on their phone rather than a computer or other device. According to an online article, a report from a mobile research company indicates that 38 percent of Chinese mobile web users only access the internet through their cell phones.

We have to conduct a hypothesis test to determine if these data provide strong evidence that the proportion of Americans who only use their cell phones to access the internet is different than the Chinese proportion of 38%.

Let p = proportion of Americans who only use their cell phones to access the internet

SO, Null Hypothesis, $H_0$ : p = 38%  {means that the proportion of Americans who only use their cell phones to access the internet is same as that of Chinese proportion of 38%}

Alternate Hypothesis, $H_a$ : p $\neq$ 38%  {means that the proportion of Americans who only use their cell phones to access the internet is different than the Chinese proportion of 38%}

The test statistics that will be used here is One-sample z proportion statistics;

                 T.S. = $\frac{\hat p-p}{\sqrt{\frac{\hat p(1- \hat p)}{n} } }$  ~ N(0,1)

where, $\hat p$ = proportion of cell phone owners who browse the internet

                 exclusively on their phone in a survey of 2,254 adults = 17%

          n  = sample of adults = 2,254

So, test statistics = $\frac{0.17-0.38}{\sqrt{\frac{0.17(1- 0.17)}{2,254} } }$

                            = -26.542

Since in the question we are not given with the significance level so we assume it to be 5%. So, at 0.05 level of significance, the z table gives critical values between -1.96 and 1.96 for two-tailed test. Since our test statistics does not lie in between the critical values of z so we have sufficient evidence to reject null hypothesis as it will fall in the rejection region.

Therefore, we conclude that the proportion of Americans who only use their cell phones to access the internet is different than the Chinese proportion of 38%.