Question

A student was asked to find a 90% confidence interval for widget width using data from a random sample of size n = 20. Which of the following is a correct interpretation of the interval 11.8 < μ < 21.7?

Check all that are correct.

• The mean width of all widgets is between 11.8 and 21.7, 90% of the time. We know this is true because the mean of our sample is between 11.8 and 21.7.
• With 90% confidence, the mean width of all widgets is between 11.8 and 21.7.
• With 90% confidence, the mean width of a randomly selected widget will be between 11.8 and 21.7.
• There is a 90% chance that the mean of a sample of 20 widgets will be between 11.8 and 21.7.
• There is a 90% chance that the mean of the population is between 11.8 and 21.7.

Answer 1

With 90% confidence, the mean width of all widgets is between 11.8 and 21.7.