Posted by **Jason L** on Monday, February 26, 2007 at 3:52pm.

It is known that the amount of time needed to change the oil in a car is normally distributed with a standard deviation of 5 minutes. A random sample of 100 oil changes yielded a sample mean of 22 minutes. Compute the 99% confidence interval estimate of the mean of the population.

Also determine the necessary sample size if you wish to be 99% confident and can tolerate an error of 1 minute.

Part 3 - With a sample size not exceeding 150 but everything else staying the same, what confidence level can be achieved?

95

96

97

98

still 99

This was answered in a previous post. For part 3, you can probably still use the same confidence interval.

## Answer This Question

## Related Questions

- Statistics - It is known that the amount of time needed to change the oil in a ...
- Statistics - It is known that the amount of time needed to change the oil in a ...
- Stats - the typical saturday the oil change facility will perform 40 oil changes...
- Stats - A simple random sample will be obtained from a normally distributed ...
- Stats - Suppose the time it takes for a purchasing agent to complete an online ...
- STATS - . The time to fly between New York City and Chicago is normally ...
- statistics - a repair shop believes that people travel more than 3500 miles ...
- stat - An oil change company advertises that they can change the oil in your car...
- Stitistics - An oil change company advertises that they can change the oil in ...
- math help - Mr. Richards has two cars that he changes the oil in every four ...

More Related Questions