According to a past poll conducted of Lexington residents, 52% indicated support for a light rail public transportation system within the city of Lexington. The sample size was 400 Lexington residents. Calculate a confidence interval for this poll using a 95% confidence level (using the formula for proportions). What is the range in which we would expect to find the true proportion of Lexington residents who support a light rail system? We will assume that the proportion from the total population is equal to the sample. If the sample size were to increase to 600 residents, what would happen to the confidence interval? Why?

Kit and Casey are each attempting to estimate the proportion of college students who can play at least one musical instrument. They each survey a different random sample of college students, and in each sample, the proportion who can play at least one musical instrument is 0.35. Kit and Casey each use their sample data to construct a confidence interval. Kit's interval is from 0.308 to 0.372 and Casey's interval is from 0.318 to 0.382. One of these intervals was computed correctly, but the other was not. Which interval must be incorrect? O Kit's interval must be incorrect. O It's impossible to answer this question without knowing the sample sizes. O It's impossible to answer this question without knowing the sample sizes or the level of confidence used for each interval. O Casey's interval must be incorrect. O It's impossible to answer this question without knowing the level of confidence used for each interval.

Tina catches a 14-pound bass.  She does not know the population mean or standard deviation.  So she takes a sample of five friends and they say the last bass they caught was 9, 12, 13, 10, and 10 pounds.  Find the t and calculate a 95% (α = .05) confidence interval.

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:

A sociologist is comparing the proportion of teenage boys who receive a text message at least once an hour to the percentage of teenage girls who do.  She has collected data from 150 men and 150 women.  Which of the following is not a condition that the sociologist should check before creating a confidence interval for the difference in population proportions?

if n = 42, p = 0.6 then construct the 98% confidence interval for the population proportion.

Vlad the Impaler promotes many of his soldiers into generals (don't ask what happened to the past generals). Haley thinks the proportion is about 79%, but wants to estimate the proportion better by sampling soldiers until her margin of error for a 93% Confidence Interval is less than 0.005. How many soldiers should Haley sample?

Siblings Mary and David are each attempting to estimate the proportion of families in their neighborhood who have five or more children. Mary selects a random sample of 50 families to survey, and she observes a sample proportion of 0.10. David selects a random sample of 100 families to survey, and he also observes a sample proportion of 0.10. Mary and David each use their sample data to construct a 95% confidence interval. Who will have the more narrow confidence interval? A. Both intervals will have the same width since the sample proportions are the same. B. Both intervals will have the same width since the level of confidence is the same for each interval. C. Both intervals will have the same width since the sample proportions are the same and the level of confidence is the same for each interval. D. Mary's interval will be more narrow than David's interval. E. David's interval will be more narrow than Mary's interval.

Debbie and Ethan are going to construct confidence intervals from the same simple random sample.  Debbie's confidence interval will have a 98% confidence interval and Ethan's will have a 95% confidence interval. A. Which confidence interval, if there is a difference will have a larger margin of error? B. Which confidence interval is more likely to cover the population mean, if there is a difference   I am using a Ti84 and need to know how to get the answer.