Question

A.) A group of engineers developed a new design for a steel cable. They need to estimate the amount of weight the cable can hold. The weight limit will be reported on cable packaging. The engineers take a random sample of 43 cables and apply weights to each of them until they break. The 43 cables have a mean breaking weight of 774.3 lb. The standard deviation of the breaking weight for the sample is 15.4 lb.

Find the 90% confidence interval to estimate the mean breaking weight for this type cable.

( _______,____________ )

Your answer should be rounded to 2 decimal places.

B.)

According to the website www.collegedrinkingprevention.gov, “About 25 percent of college students report academic consequences of their drinking including missing class, falling behind, doing poorly on exams or papers, and receiving lower grades overall.” A statistics student is curious about drinking habits of students at his college. He wants to estimate the mean number of alcoholic drinks consumed each week by students at his college. He plans to use a 90% confidence interval. He surveys a random sample of 50 students. The sample mean is 3.90 alcoholic drinks per week. The sample standard deviation is 3.51 drinks.

Construct the 90% confidence interval to estimate the average number of alcoholic drinks consumed each week by students at this college.

( ______, ________ )

Your answer should be rounded to 2 decimal places.

Answer 1