Confidence Intervals

Which of the following is the definition of a "point estimate?"

• The midpoint of the confidence interval

• The sample size

• The population

• The standard deviation

Tags

CCSS.HSS.IC.B.4

The amount added and subtracted to the statistic.

• Margin of error

• Statistic

• Population

• Point estimator

Tags

CCSS.HSS.IC.B.4

What is the point estimator for the interval (5 , 13)?

• 9

• 10

• 11

• 8

Tags

CCSS.HSS.MD.A.2

CCSS.HSS.MD.A.3

What is the margin of error for the interval (6.8, 12.9)?

• 3.05

• 9.85

• 5.83

• 8.41

Tags

CCSS.HSS.IC.B.4

An IQ test was given to a simple random sample of 75 students at a certain college. The sample mean score was 105.2. Scores on this test are known to have a standard deviation of 10. It is desired to construct a 90% confidence interval for the mean IQ scores of the students at the college.

Find the point estimate.

• 10

• 105.2

• .90

• 75

Tags

CCSS.HSS.IC.B.4

An IQ test was given to a simple random sample of 75 students at a certain college. The sample mean score was 105.2. Scores on this test are known to have a standard deviation of 10. It is desired to construct a 90% confidence interval for the mean IQ scores of the students at the college.

Find the Critical Value for the mean.

• 1.67

• 1.28

• -1.67

• -1.28

Tags

CCSS.HSS.IC.A.1

CCSS.HSS.IC.B.4

CCSS.HSS.ID.A.4

The lifetime of a certain type of batter is known to be normally distributed with a standard deviation of 20 hours. A sample of 50 batteries had a mean lifetime of 120.1 hours. Construct a 99% confidence interval for the mean lifetime of this type of battery.

• (111.2, 128.9)

• (114.53, 131.23)

• (112.52, 127.68)

• (118.43, 122.43)

Tags

CCSS.HSS.IC.A.1

CCSS.HSS.IC.B.4

CCSS.HSS.ID.A.4

If the 95% Confidence Interval for a population mean is (114.56, 125.54), then is it likely that the true population mean µ is greater than 130?

• I have no clue

• Not enough information given

• Yes

• No

Tags

CCSS.HSS.IC.A.1

CCSS.HSS.IC.B.4

Find the Critical Value for an 86% Confidence Level for a proportion.

• 1.48

• -1.48

• 1.96

• -1.96

Tags

CCSS.HSS.IC.B.4

CCSS.HSS.ID.A.4

True or False:

The more confident you want to be, the smaller your confidence interval will be.

• True

• False