2. You are going to construct a 90% confidence interval for the proportion of adults that have a post-secondary education. You want the margin of error to be .03. Your initial guess is that 35% of the population has a postsecondary education. What should the sample size be to achieve this margin of error?

An educator wants to construct a 99% confidence interval for the proportion of elementary school children in Michigan who are proficient in reading. Estimate the sample size needed to conduct this survey and assume that there there is no information available to be used from a previous study. Use a margin of error of 3%.   What is the sample size:   _________

Suppose we know that a confidence interval for a population proportion is (0.105,0.355), with a sample proportion of p̂=0.23. What is the margin of error?

I'm having trouble trying to figure out how to work the problem below out.    Let’s say that 44 percent of the 1,300 U.S. adults who responded to a poll about marijuana legalization said they support legalization. Let’s also say the margin of error for the results is +/- 3 percentage points. The margin of error tells us there’s a high probability that nationwide support for marijuana legalization falls: The correct interpretation of this confidence interval is:

Next question If a sample proportion is 0.68, which of the following could be a 90% confidence interval for the population proportion? ..... Select all that apply. A. Lower bound: 0.59; Upper bound: 0.77 B. Lower bound: 0.66; Upper bound: 0.70 OC. Lower bound: 0.50; Upper bound: 0.77 D. Lower bound: 0.77; Upper bound: 0.95 E. Lower bound: 0.67; Upper bound: 0.71 F3 F4 F5 F7 F8 24 4. %23 2 3. 6. Left control option command

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In the Star and Tribune newspaper, there is an article entitled "1 in 8 school buses fail tests." The article says that the overall statewide proportion of school buses that fail safety tests is 9%. However, one bus company has a higher rate of over 12%. Assume that we want a new estimate for the statewide proportion of school buses that fail the safety inspection. How large a sample would you have to take in order to construct a 95% confidence interval estimate for the true proportion of buses that fail the inspection and achieve a margin of error of plus or minus 2%? (your answer should be an integer)

Suppose a sample of 9 customers spends an average of $200 with a standard deviation $20 what is a 95% confidence interval for the sample mean. Use the fact that 95% of sample means are within 2.306 standard errors of the sample mean.