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Answer:
85.71% probability that it takes Evelyn less than 38 minutes given that it takes less than 41 minutes for her to go grocery shopping
Step-by-step explanation:
An uniform probability is a case of probability in which each outcome is equally as likely.
For this situation, we have a lower limit of the distribution that we call a and an upper limit that we call b.
The probability that we find a value X lower than x is given by the following formula.
Uniformly distributed between 20 minutes and 44 minutes.
This means that .
What is the probability that it takes Evelyn less than 38 minutes given that it takes less than 41 minutes for her to go grocery shopping
We know that it takes less than 41 minutes, so we can update b to 41.
So
85.71% probability that it takes Evelyn less than 38 minutes given that it takes less than 41 minutes for her to go grocery shopping
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%.
<em>Let p = proportion of Americans who only use their cell phones to access the internet</em>
SO, Null Hypothesis, : 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, : p
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 <u>One-sample z proportion statistics</u>;
T.S. = ~ N(0,1)
where, = 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, <em><u>test statistics</u></em> =
= -26.542
<em>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.</em>
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%.