Chapter 8, Problem 8.21AC

Suppose a marketing company computed a 96% confidence interval for the true proportion of customers who click on ads on their smartphones to be (0.59 , 0.71)

In a random sample of 500 adults, 410 described themselves as vegetarians. Construct a 95% confidence interval for the proportion of all adults who describe themselves as vegetarians.

A Dean of a certain business school is interested in the difference in proportions of A's given by Professors I & II.  Suppose the dean has access to 800 grade reports from each professor.  It turns out that 240 students received A's from Professor I and 160 students received A's from Professor II. Construct a 95% confidence interval for the true differences in proportions of A's given by the two professors.

If a Random Sample of 450 adults includes 155 who identify as happy, compute an 80% confidence interval for the true proportion of adults who are happy.

Part 3. Assume that an advertisement claimed 32% of cellphone owners aged 18-24 have an android phone. Does the confidence interval contradict this claim? the confidence interval (a) does (b) does not contradict the claim because 0.32 (a)is (b) is not contained in the conf

A business conducts a random sample of 89 of its customers and find that 44 of them think the company should expand. Find an 80% confidence interval for the proportion of customers who think the company should expand. Use three decimals when computing the point estimate and when giving your final answer.

a critic points out that this 95 %  confidence interval is only accurate if the statistic follows a normal distrubution , or if the normal model is a good approximation. is this true for this data? explain

Researchers are looking to see what proportion of students will report cheating if they see it happen. A SRS of 172 undergraduates is collected and 19 respond that they would report cheating if they saw it happen. What is the point estimator?

We have developed a new drug used to reduce fever and want to test its efficacy. Ten ER patients who are running a fever agree to take the new drug instead of the traditional treatment. Their temperatures are taken before the drug is administered and 30 minutes after taking the drug. The results are recorded in the Excel file below. Use the data to construct and interpret a 99% confidence interval for the mean change in temperatures of patients after taking this drug using Excel. Be sure to include any explanation necessary along with a sentence that explains what the interval means.   In excel