Interpreting and Constructing Confidence Interval

Which of the following is an example of an interval estimate?

• point estimate 

• critical value

• confidence interval

• statistic

A __________ gives an interval of plausible values for the _____________. 

• confidence interval, statistic

• point estimate, parameter

• point estimate, statistic

• confidence interval, parameter

Construct a 90% confidence interval of a random sample size of 19 cows with a mean of 155.526 and a standard deviation of 19.993. 

• (146.54, 164.52)

• (147.57, 163.48)

• (147.59, 163.46)

• (143.69, 167.36)

When interpreting the confidence interval, make sure that you are describing the 

• statistic

• parameter

A confidence interval for the mean score of a test is (75, 85). What is the margin of error?

• 5

• 10

• 15

• 20

If the margin of error in a confidence interval is 4, what is the range of the confidence interval around a sample mean of 50?

• 46 to 54

• 48 to 52

• 45 to 55

• 49 to 51

Identify the confidence interval used in the figure below if each shaded area is equal to 0.05.

• 90%

• 95%

• 98%

• 99%

• A
• B
• C
• D

What is the effect of increasing the sample size on the width of the confidence interval, assuming the confidence level remains the same?

• The width of the confidence interval increases.

• The width of the confidence interval decreases.

• The width of the confidence interval stays the same.

• The width of the confidence interval doubles.

What is the main purpose of using a 95% confidence interval in statistics?

• To estimate the range within which the true population parameter lies with 95% certainty.

• To confirm the exact value of the population mean.

• To calculate the standard deviation of the sample.

• To determine if the sample data is normally distributed.