Confidence Intervals General & props

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

• 10

• 9.5

• 9

• -5

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

• 9.85

• 3.05

• 3.50

• 6.8

Which of the following actions would produce a confidence interval with a smaller width assuming all other contingencies remained constant?

• Using a higher confidence level

• Using a lower confidence level

Which of the following changes to a study would result in a narrower confidence interval?

• increasing the confidence level, increasing the sample size
• decreasing the confidence level, decreasing the sample size
• increasing the confidence level, decreasing the sample size
• decreasing the confidence level, increasing the sample size.

Which of the following values below represents the critical value for a 98% confidence interval?

• 2.326
• 2.054
• 1.645
• 3.091

True or False:

The larger your confidence interval is, the more sure (higher confidence level) you can be.

• True

• False

True or False:

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

• True

• False

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

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?

• Yes

• No

• Not enough information

• I have no idea what you're asking of me

The symbol for the sample proportion is __________.

• Z_c
• p̂
• E
• q