Posted by **bob** on Wednesday, March 30, 2011 at 10:13pm.

A university dean wishes to estimate the average number of hours his part-time instructors teach per week. The standard deviation is 2.6 hours. How large a sample must be selected if he wants to be 95% confident of finding whether the true mean differs from the sample mean by 1 hour?

- statistics -
**MathGuru**, Thursday, March 31, 2011 at 11:25am
Formula:

n = [(z-value * sd)/E]^2

...where n = sample size, z-value will be 1.96 using a z-table to represent the 95% confidence interval, sd = 2.6, E = 1, ^2 means squared, and * means to multiply.

Plug the values into the formula and finish the calculation. Round your answer to the next highest whole number.

## Answer this Question

## Related Questions

- statistics - To determine how many hours per week freshmen college students ...
- Statistics - 28. A group of statistics students decided to conduct a survey at ...
- Statistics - A survey among freshmen at a certain university revealed that the ...
- statistics - The Office of Student Services at a large western state university ...
- statistics - Suppose that in the aerobic exercise group we also measured the ...
- statistics - A medical board claim that the mean number of hours worked per week...
- statistics - A survey was conducted to measure the number of hours per week ...
- Math-one more - The average length of time, per week, that students at a certain...
- biostatistics - 7. Consider again the data in problem #6. Suppose that in the ...
- Statistics - A group of statistics students decided to conduct a survey at their...