Discuss the difference between the 95% and 99% confidence levels. What are the corresponding alpha levels and how confident is the researcher in the results?

A poll reported that only 645 out of a total of 2029 adults in a particular region said they had a​ "great deal of​ confidence" or​ "quite a lot of​ confidence" in the public school system. This was down 5 percentage points from the previous year. Assume the conditions for using the CLT are met. Find an 80​% confidence interval and interpret it. The 80​% confidence interval for the proportion that express a great deal of confidence or quite a lot of confidence in the public schools is ____.

A 95% confidence interval is constructed in order to estimate the proportion of adults who own an iPhone. The resulting interval has a margin of error of 0.043. Which of the following would be the margin of error for a 90% confidence interval based on the same sample of data?

You are interested in constructing a 99% confidence interval for the proportion of all caterpillars that eventually become butterflies. Of the 417 randomly selected caterpillars observed, 45 lived to become butterflies. Round answers to 4 decimal places where possible.

you want to find out the percent of people who use an iPhone so you survey 120 random adults of whom 57 use an iPhone. what is the 95% confidence interval for P the put portion of all adults who use iPhone

A researcher gathered a sample of participants who volunteered for a studying of phobias. She measured anxiety level of participants as they viewed photos of spiders and again when they viewed puppies. Which statistical test is appropriate for this study and why?

The Athletics Department at a high school is interested in the difference in the run times between 11th and 12th grade students. Suppose the 11th grade students make up the first sample while the 12th grade students make up the second.Using a confidence level of 95%, the confidence interval found was (−1.8,2.9)(-1.8,2.9).Which of the following is the correct interpretation? We are 95% confident that the run times of the 11th grade students are, on average, faster than those of the 12th grade students. We are 95% confident that the run times of the 11th grade students are, on average, slower than those of the 12th grade students. We are 95% confident that the run times of the 11th grade students are, on average, about the same as those of the 12th grade students.

If n = 440 and p = 0.52, construct a 90% confidence interval. %3D Give your answers to three decimals

A chemist measures the haptoglobin concentrations (in grams per liter) in the blood of eight healthy adults.  Following are the values: 1.82   3.32   1.07   1.27   0.49   3.79   0.15   1.98  At the 2% significance level, test the claim that the mean haptoglobin concentration in adults is less than two grams per liter.    What type of error could you have made in your decision?

To test the effect of a physical fitness course on one's physical ability, the number of sit-ups that a person could do in one minute, both before and after the course, was recorded. Ten individuals are randomly selected to participate in the course. The results are displayed in the following table. Using this data, find the 90%90% confidence interval for the true difference in the number of sit-ups each person can do before and after the course. Assume that the numbers of sit-ups are normally distributed for the population both before and after completing the course. Sit-ups before 2929 3636 2828 5050 2323 3737 3232 2929 4040 2121 Sit-ups after 4545 3838 3535 5656 4141 5555 4747 4545 4444 2626 Copy Data Step 1 of 4:  Find the point estimate for the population mean of the paired differences. Let x1x1 be the number of sit-ups before taking the course and x2x2 be the number of sit-ups after taking the course and use the formula d=x2−x1d=x2−x1 to calculate the paired…