Suppose that a jewelry store tracked the amount of emeralds they sold each week to more accurately estimate how many emeralds to keep in stock. At the end of one year, the store used the weekly sales information to construct a 95% confidence interval for the mean number of emeralds sold per week. The confidence interval they calculated was (3.25,4.51). Use the confidence interval to find the point estimate for the mean and the margin of error. Give your answers precise to two decimal places.

In one city, 27.8% of the 9000 students surveyed said they eat at the school cafeteria. Find the 95% confidence interval for the proportion of students that said they eat at the school cafeteria. Give answer as a percent rounded to one decimal place.

Use the confidence interval to find the estimated margin of error. Then find the sample mean. A biologist reports a confidence interval of (1.9.3.1) when estimating the mean height (in centimeters) of a sample of seedlings. The estimated margin of error is The sample mean is

A Gallup survey of 2324 adults (at least 18 years old) in the U.S. found that 417 of them have donated blood in the past two years. Construct a 90% confidence interval for the population proportion of adults in the U.S. who have donated blood in the past two years. Round your answer to three decimal places. Use Z = 1.645. Use the unrounded values in Excel to find the answers to #2, #3 and #4 1. Find the sample proportion of adults in the U.S. who have donated blood in the past two years. Round your answer to three decimal places. 2. The standard error for sample proportion has a value of V 3. The margin of error has a value of 4. Construct the 90% confidence interval for adults who have donated blood in the past t

A statistics practitioner took a random sample of 50 observations from a population whose standard deviation is 30 and computed the sample mean to be 109. Note: For each confidence interval, enter your answer in the form (LCL, UCL). You must include the parentheses and the comma between the confidence limits.   A. Estimate the population mean with 95% confidence. Confidence Interval = B. Estimate the population mean with 90% confidence. Confidence Interval = C. Estimate the population mean with 99% confidence. Confidence Interval =

A statistics practitioner took a random sample of 55 observations from a population whose standard deviation is 28 and computed the sample mean to be 110. Note: For each confidence interval, enter your answer in the form (LCL, UCL). You must include the parentheses and the comma between the confidence limits. A. Estimate the population mean with 95% confidence. Confidence Interval =| B. Estimate the population mean with 90% confidence. Confidence Interval = C. Estimate the population mean with 99% confidence. Confidence Interval =

A Surprising fact indicates that a small proportion of teens use a password on their mobile device. A poll chooses a simple random sample of 120 teens and asks if they use a password on their mobile device. The results showed that 56 of teens in our  sample used a password on their mobile device. Find a 90 % confidence interval for the proportion of teens who use a password on their mobile device. Interpret your confidence interval.

In a sample of 500 Canadians, it was found that 400 people preferred apple products. In a sample of 700 Americans it was found that 600 preferred apple products. Is the proportion Canadians who prefer apple products less than Americans. 1. Construct 95% confidence interval for difference of proportions. 2. From the confidence interval, do you think that the proportion of Canadians who prefer apple products is different from Americans.

A successful basketball player has a height of 6 feet 11 ​inches, or 211 cm. Based on statistics from a data​ set, his height converts to the z score of 5.17. How many standard deviations is his height above the​ mean?

Please help with question 5 a-b