We want to estimate the population mean within 21, with a 90% level of confidence. The population standard deviation is estimated to be 60. How large a sample is required?

We want to estimate the population mean within 21, with a 90% level of confidence. The...
Please use excel for work.
20. We want to estimate the population mean within 5, with a 99% level of confidence. The population standard deviation is estimated to be 15. How large a sample is required?
A population is estimated to have a standard deviation of 12. We want to estimate the population mean within 2 with a 99 percent level of confidence. How large a sample is required?
A population is estimated to have a standard deviation of 12. We want to estimate the population mean within 2, with a 95% level of confidence. How large a sample is required? (Round up your answer to the next whole number.)
A population is estimated to have a standard deviation of 10. We want to estimate the population mean within 2, with a 95% level of confidence. How large a sample is required? a. 98 b. 97 c. 96 d. 95
We want to obtain a sample to estimate a population mean. Based on previous evidence, researchers believe the population standard deviation is approximately σ=74. We would like to be 90% confident that the esimate is within 1 of the true population mean. How large of a sample size is required? n=
We want to estimate the mean starting salary in a population of graduates. Approximately normally distributed. Standard deviation = 10 In a random sample of 31 graduates, the mean starting salary was 61.8 and the standard deviation was 12. 1. What is the lower (smaller) endpoint of the 90% confidence interval for the population mean? 2. What is the upper (larger) endpoint of the 90% confidence interval for the population mean? 3. If null hypothesis = 60 and alternate hypothesis...
What is the minimum sample size required to estimate a population mean with 90% confidence if the population standard deviation is estimated to be 30 and the desired margin of error is 2?
If we want to provide a 90% confidence interval for the mean of a population and the population standard deviation is known, the correct Z value is 0.95 1.96 0.485 1.645
You want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard deviation is approximately σ=61.9σ=61.9. You would like to be 90% confident that your estimate is within 1.5 of the true population mean. How large of a sample size is required?
You want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard deviation is approximately σ = 37.2 σ = 37.2 . You would like to be 90% confident that your estimate is within 1.5 of the true population mean. How large of a sample size is required? n=?