Excel Statistics 80: Confidence Interval Sigma Known

[UpcomingJedi]

Do you have a video on how to change this to include the standard error of the mean of n observations instead of just the population standard deviation where Z=(xbar-mu)/sigma/sqrt (n) to figger out something like this, in a hurry? Mu=63, sigma=13, and n=25. Probability that: a. x>65, b. x<59 and c. area between 59 and 65. Answers: a.= .2206, b.=.0618 and c.=.4382. Thank you.

[deljanzen]

If you know that the confidence interval for a population mean was reported to be 152 to 160 and the population standard deviation is 15, how do you determine the sample size in this study using excel?

Thanks Del