{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Confidence_Interval

# Confidence_Interval - Confidence Interval for a Population...

This preview shows pages 1–2. Sign up to view the full content.

Confidence Interval for a Population Mean 1. A physician wanted to estimate the mean length of time μ that a patient had to wait to see him after arriving at the office. A random sample of 36 patients showed a mean waiting time of 23.4 minutes and a standard deviation of 7.2 minutes. Find a 96% confidence interval for μ . 2. The owner of a small computer company wished to estimate the mean download rate μ for the company's update to one of its programs. Forty-nine downloads gave a mean rate of 3.1 and a standard deviation of 1.6 kilobits per second. Find a 98% confidence interval for μ . 3. Barbara wanted to estimate the mean connection time μ to the Internet. She connected 25 times with a mean of 42 and a standard deviation of 5.2 minutes. Find a 90% confidence interval for μ . 4. A study was done to estimate the mean annual growth μ in a population of Conuspennaceus trees in Hawaii. For those with an initial size of 2.41-2.60 centimeters, a sample of size 12 yielded a mean annual growth of .72 centimeter and a standard deviation of .31 centimeter. Find a 90% confidence interval for the population mean μ of annual growth (of those trees with an initial size of 2.41-2.60 centimeters). 5. 16 pieces of a plastic are randomly selected, and the breaking strength of each piece is recorded in pounds per square inch. Suppose that: X = 26 and s = 1.5 pounds per square inch. Find a 99% confidence interval for the mean breaking strength μ . If you were to obtain 200 those 99% confidence intervals for the mean breaking strength, about how many can be expected to contain μ ?

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 3

Confidence_Interval - Confidence Interval for a Population...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online