QCAA Psychology - Confidence Intervals

What is a confidence interval?

• A range of values that includes the true mean of the population

• A range of values that includes the sample mean

• A range of values that includes the standard deviation

• A range of values that includes the variance

What does a 95% confidence interval mean?

• There is a 95% chance that the sample mean is accurate

• There is a 95% chance that the population mean is accurate

• There is a 5% chance that the sample mean is accurate

• There is a 5% chance that the population mean is accurate

Why do researchers use confidence intervals?

• To estimate the population parameters based on a sample

• To estimate the sample parameters based on a population

• To determine the standard deviation of the population

• To determine the standard deviation of the sample

How is a confidence interval calculated?

• By dividing the sample mean by the standard deviation

• By multiplying the sample mean by the standard deviation

• By adding and subtracting the margin of error from the sample mean

• By adding and subtracting the margin of error from the population mean

What happens to the confidence interval as the sample size increases?

• It becomes wider

• It becomes narrower

• It remains the same

• It becomes more accurate

How should confidence intervals be reported?

• As a single value

• As a range of values

• As a percentage

• As a standard deviation

What is the purpose of a confidence level?

• To determine the accuracy of the sample mean

• To determine the accuracy of the population mean

• To determine the range of values in the confidence interval

• To determine the probability that the confidence interval includes the true mean

What does the standard deviation measure?

• The average value in a sample

• The spread of values in a sample

• The accuracy of the sample mean

• The accuracy of the population mean

What does a box plot display?

• The range of values in a sample

• The spread of values in a sample

• The median and interquartile range

• The confidence interval

What does a confidence interval reveal?

• The range of values in a sample

• The range of values in a population

• The true value of a population parameter

• The true value of a sample parameter