I don't need explain, just result. Thank you sm.

Question 4:

Researchers observed 50 random people brush their teeth and recorded the number of seconds each person spent brushing. From the sample, they found a mean time of 47.2 seconds. Further, their calculations revealed that this estimate is within a margin of error of 2.5 from the true average time that all people spend brushing their teeth. Write the interval estimate that will estimate the true average time that people spend brushing their teeth. Write your answer in interval notation: (______ , ______ )

Question 5:

A student was asked to find a 90% confidence interval for widget width using data from a random sample of size n = 27. Which of the following is a correct interpretation of the interval 13.2 < < 33.7?

NOTE: A "widget" is a generic term for a device or object made in a factory.

Check which is correct.

A. With 90% confidence, the mean width of a randomly selected widget will be between 13.2 and 33.7.

B. There is a 90% chance that the mean of the population is between 13.2 and 33.7.

C. The mean width of all widgets is between 13.2 and 33.7, 90% of the time. We know this is true because the mean of our sample is between 13.2 and 33.7.

D. With 90% confidence, the mean width of all widgets is between 13.2 and 33.7.

E. There is a 90% chance that the mean of a sample of 27 widgets will be between 13.2 and 33.7.

Question 6:

A grocery store wishes to estimate the mean age of canned food in their store. They take a sample of 41 items and found a mean of 10.7 months with a standard deviation of 4.9 month. Find the 95% confidence interval for the age of the canned food items. Enter your answer accurate to one decimal place. With 95% confidence the sample estimates the mean age of canned food items to be between_______ months and_______ months.