1. A random sample of 35 two-year colleges in 2008-2009 collected data on the in-state tuition costs and enrollment totals. Based on the sample, the researchers estimated the mean in-state tuition for all two-year colleges to be $2,380. Which form of statistical inference does this conclusion represent?

Group of answer choices

a)Interval estimation

b)Point estimation

c)Hypothesis testing

2.The makers of Mini-Oats cereal have an automated packaging machine that is set to fill boxes with 24 ounces of cereal. At various times in the packaging process, we select a random sample of 100 boxes to see whether or not the machine is filling the boxes with an average of 24 ounces of cereal.

Which of the following is a statement of the null hypothesis?

Group of answer choices

a)The machine fills the boxes with the proper amount of cereal. The average is 24 ounces.

b)The machine is not putting enough cereal in the boxes. The average is less than 24 ounces.

c)The machine is not filling the boxes with the proper amount of cereal. The average is not 24 ounces.

3)A sheet metal manufacturer is making 10-gauge sheet metal, which is supposed to be 3.416 mm thick. One of the pieces of manufacturing equipment was suspected of malfunctioning, so the manufacturer tested a random sample of 100 pieces of steel to make sure the average steel thickness is 3.416 mm.

Which of the following is a statement of the null hypothesis?

Group of answer choices

a)The equipment is making the sheet metal too thick. The average average steel thickness is greater than 3.416 mm.

b)The equipment is working properly. The average average steel thickness is 3.416 mm.

c)The equipment is not working properly. The average average steel thickness is not 3.416 mm.