Question 21(1 point)

Select the most appropriate response.

Data collected by child development scientists produced the following 90% confidence interval for the average age (in months) at which children say their first word:10.4 < < 13.8.

In this example, what does the phrase90% confidentmean?

Question 21 options:

There is a 90% chance that the sample mean is between10.4 and 13.8 months.

If many samples are drawn, the computed confidence intervals will contain the population mean approximately 90% of the time.

There is a 90% chance that the population mean is between10.4 and 13.8 months.

If many samples are drawn, the population mean will be between 10.4 and 13.8 months approximately 90% of the time.

Question 22(1 point)

Select the most appropriate response.

Which of the following is a benefit of increasing the sample size when trying to estimate the mean from a sample average?

Question 22 options:

A reduction in the bias of the estimate.

A reduction in the variability of the estimate.

An increase in the width of the resulting confidence interval.

There will be no benefit because the population has not changed.

Question 23(1 point)

Construct the requested confidence interval.

An electronics company just finished designing a new tablet computer and is interested in estimating its battery-life.A random sample of 20 laptops with a full charge was tested and the battery-life was found to be approximately normal with a mean of 6 hours and a sample standard deviation of 1.5 hours.Which of the following is the correct form for a 99% confidence interval?

Question 23 options:

CI

.99

()=62.576(0.3354)

CI

.99

()=62.576(1.5)

CI

.99

()=62.861(0.3354)

CI

.99

()=62.861(1.5)