Statistics problems

4. A random sampleof 100 light bulbs is selected. Sixty were found to burn for more than 1,000 hours. Develop a 90 percent confidence intervalfor the proportion of bulbs that will burn more than 1,000 hours.

5. A health maintenance organization (HMO) wants to estimate the meanlength of a hospital stay. How large a sample of patient records is necessary if the HMO wants to be 99 percent confident of the estimate and wants the estimate to be within plus or minus 0.2 days? An earlier study showed the standard deviationof the length of stay to be 0.25 days.

6. A large bank believes that one-third of its checking customers have used at least one of the bank’s other services during the past year. How large a sample is required to estimate the actual proportion within a rangeof plus and minus 0.04? Use the 98 percent level of confidence.

See attached file for full problem description.

Please see the attached file.

4. A random sample of 100 light bulbs is selected. Sixty were found to burn for more than 1,000 hours. Develop a 90 percent confidence interval for the proportion of bulbs that will burn more than 1,000 hours.

Proportion of bulbs that burn for more than 1000 hours = p = 0.60
Proportion of bulbs that burn for more than 1000 …

This posting contains solutions to following statistics problems.