Question

A survey of 36 adults found that the mean age of a person’s primary vehicle is 5.6 years with a standard deviation of 1.2 years. Compute a 99% confidence interval for the mean age of all primary vehicles. Round your answers to 3 decimal places.

Lower Confidence Limit =

Answer 1

To compute a 99% confidence interval for the mean age of all primary vehicles, substitute the values into the formula: Confidence interval = sample mean ± (critical value * standard deviation/square root of sample size). The lower confidence limit is approximately 5.334.

Step-by-step explanation:

To compute a 99% confidence interval for the mean age of all primary vehicles, we can use the formula:

Confidence interval = sample mean ± (critical value * standard deviation/square root of sample size)

Since the sample mean age is 5.6 years and the standard deviation is 1.2 years, we need to find the critical value for a 99% confidence level. Using a standard normal distribution table or a calculator, we find that the critical value is approximately 2.617. The sample size is 36.

Substituting these values into the formula, we get:

Confidence interval = 5.6 ± (2.617 * 1.2/√36)

Calculating the confidence interval, we get:

Confidence interval = [5.6 - (2.617 * 1.2/√36), 5.6 + (2.617 * 1.2/√36)]

Rounding to 3 decimal places, the lower confidence limit is approximately 5.334.