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

Find the 90% confidence interval to estimate the mean breakingweight 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 consequencesof their drinking including missing class, falling behind, doingpoorly on exams or papers, and receiving lower grades overall.” Astatistics student is curious about drinking habits of students athis college. He wants to estimate the mean number of alcoholicdrinks consumed each week by students at his college. He plans touse a 90% confidence interval. He surveys a random sample of 50students. The sample mean is 3.90 alcoholic drinks per week. Thesample standard deviation is 3.51 drinks.

Construct the 90% confidence interval to estimate the averagenumber of alcoholic drinks consumed each week by students at thiscollege.

( ______, ________ )

Your answer should be rounded to 2 decimal places.