xtremechik2
New member
- Joined
- Apr 9, 2010
- Messages
- 1
I'm currently stuck on these 2 problems, if anybody could help that would be great.
1. A researcher is interested in estimating the average salary of police officers in a large city. She wants to be 95% confident that her estimate is correct. If the standard deviation is $1050, how large a sample is needed to get the desired information and to be accurate within $200?
2. Find the 99% confidence interval for the variance and standard deviation of the weights of 25 one gallon containers of motoroil, if a sample of 14 containers has a variance of 3.2. The weights are given in ounces. Assume the variable is normally distributed.
1. A researcher is interested in estimating the average salary of police officers in a large city. She wants to be 95% confident that her estimate is correct. If the standard deviation is $1050, how large a sample is needed to get the desired information and to be accurate within $200?
2. Find the 99% confidence interval for the variance and standard deviation of the weights of 25 one gallon containers of motoroil, if a sample of 14 containers has a variance of 3.2. The weights are given in ounces. Assume the variable is normally distributed.