Confidence Intervals Review

A sample size of n = 64 is drawn from a population whose standard deviation is σ = 5.6.

Find the margin of error for a 99% confidence interval for µ.

• 1.799

• 1.798

• 1.803

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.

What is the point estimate?

• 75

• 105.2

• 10

• 0.90

Tags

CCSS.HSS.IC.B.4

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

• 10

• 9.5

• 9

• -5

Tags

CCSS.HSS.IC.B.4

In a survey of 104 students, it was found that 79 went to the homecoming game this year.

Calculate a 99% confidence interval for p.

• (.59, .79)

• (.62, .85)

• (.60, .90)

• (.65, .87)

Tags

CCSS.HSS.IC.B.4

For a sample, the 95% confidence interval is (0.202, 0.482).

What is the margin of error of this sample?

• .21

• .344

• .14

• .342

Tags

CCSS.HSS.IC.B.4

If using a 95% confidence level, what value of z should you use?

Tags

CCSS.HSS.ID.A.4

If the mean of a sample is 203 and the margin of error is 4.6, what would be a reasonable mean for the population?

• 99.2

• 198.3

• 207.2

• 207.7

Tags

CCSS.HSS.IC.B.4

1. A 95% confidence level means...

• A. There is a 95% probability that the true population parameter falls within the interval.

• B. There is a 5% probability that the true population parameter falls within the interval.

• C. If we were to repeat the sampling process many times, 95% of the intervals constructed would contain the true population parameter.

Tags

CCSS.HSS.IC.B.4

A 90% confidence interval for a population mean is determined to be 800 to 900. If the confidence is increased to 95% confidence while the sample statistics and sample size remain the same, the confidence interval

• becomes wider
• becomes narrower
• does not change

Tags

CCSS.HSS.IC.B.4

Increasing the sample size __________ the confidence interval. 

• increases
• decreases
• does not affect
• there is not enough evidence to determine the answer