A survey of nonprofit organizations showed that online fundraising has increased in the past year. Based on a random sample of 50 ​nonprofits, the mean​ one-time gift donation in the past year was ​$​37, with a standard deviation of ​$7. Construct a 99​% confidence interval estimate for the population​ one-time gift donation.

In a survey, 26 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $40 and standard deviation of $6. Find the margin of error at a 90% confidence level.

In a recent sample of 89 used cars sales costs, the sample mean was $6,225 with a standard deviation of $3,151. Assume the underlying distribution is approximately normal.   Which distribution should you use for this problem? Construct a 95% confidence interval for the population mean cost of a used car.

Suppose a sample of 30 students are given an IQ test. The sample has a standard deviation of 12.23 points. Assuming IQ test score follow a normal distribution, suppose the researcher wishes to obtain a 90% confidence interval for the population standard deviation.

Suppose that your sample size is 30 and that you wish to construct a 95% confidence interval. Your sample standard deviation is 40.9. Estimate your margin of error (MOE) using this information and the t-distribution table. Estimate your response to the first decimal point.

A survey of 3737 randomly selected homeowners finds that they spend a mean of $73$73 per month on home maintenance with a standard deviation of $10$10 per month.   Construct a 90%90% confidence interval for the mean amount of money spent per month on home maintenance by all homeowners. Round to the nearest cent.

At the end of 2015, 2016, and 2017, the average prices of a share of stock in a portfolio were $34.83, $34.65, and $31.26 respectively. To investigate the average share price at the end of 2018, a random sample of 30 stocks was drawn and their closing prices on the last trading day of 2018 were observed with a mean of 33.583 and a standard deviation of 19.149. Estimate the average price of a share of stock in the portfolio at the end of 2018 with a 95% confidence interval. Compare and Briefly discuss

A survey of 73 randomly selected homeowners finds that they spend a mean of $74 per month on home maintenance. Construct a 95% confidence interval for the mean amount of money spent per month on home maintenance by all homeowners. Assume that the population standard deviation is $16 per month. Round to the nearest cent.

A random sample of 64 shoppers showed that they spend an average of $27.31 per visit at the Sunday Mornings Bookstore. The standard deviation of the population is $2.14. Find the 90% confidence interval of the true mean. Please include all work showing how you found your answer.

From a random sample of 48 days in a recent year, U.S. gasoline prices had a mean of $2.34 and a standard deviation of $0.32. Construct a 95% confidence interval for the population mean