The body temperature of healthy human beings can be assumed to have a normal distribution with mean and standard deviation . Body temperature measurements taken from a sample of 130 healthy individuals shows the sample mean temperature to be 98.249O F and sample standard deviation to be 0.733O F. Based on this information:
• Find a 95% confidence interval for
• The usually assumed body temperature for a healthy individual is 98.6O F. Does this fall in the above confidence interval?
• Find a 90% confidence interval for
• A large employer in Toledo, Ohio is considering offering its employees certain facilities for child care. As a part of the feasibility study, the employer wants to estimate the current mean weekly cost of child care for their employees who use child care services. A random sample of 10 employees who use child care services reveals the following amounts spent last week:
$107, $92, $97, $95, $105, $101, $91, $99, $104, $95.
Find a 90% confidence interval for the population mean. State any assumptions you make in arriving as this result.
Formulas:
CI90 = mean ± 1.645 (sd/√n)
CI95 = mean ± 1.96 (sd/√n)
For the first part, substitute the mean, standard deviation, and sample size into the appropriate formulas to determine the confidence intervals. This will help you answer the questions about the intervals.
For the second part, find mean and standard deviation of the data listed. Substitute into the appropriate confidence interval to calculate.
I hope this will help get you started.