1.Use margin of error, confidence level, and standard deviation to find the minimum sample size required to estimate an unknown population mean.

Margin of error: $124, Confidence level; 99%, σ = $560


2.Find the margin of error for 95% confidence interval used to estimate the population propprtion.

In a clinical test with 2333 subjects, 50% showed improvement from the treament.



Thank, I'm having a hard time figure how to get the answers here.

1.Use margin of error, confidence level, and standard

deviation to find the minimum sample size required to estimate an unknown population mean.

Margin of error: $124, Confidence level; 99%, σ = $560

Do you have a stats book? If so, this formula should be in there:

n=\left(\frac{z\cdot\sigma}{E}\right)^{2}

You are given all the necessary info. E is the margin of error. You should know what sigma and z are. Look up z for a 99% CI in the z table.



2.Find the margin of error for 95% confidence interval used to estimate the population proportion.

In a clinical test with 2333 subjects, 50% showed improvement from the treatment.


Proportions has a minimum sample formula as well.

E=z\sqrt{\frac{pq}{n}}

You have all you need to find E.

Do you have a stats book?. If so, this formula should be in there:

n=\left(\frac{z\cdot\sigma}{E}\right)^{2}

You are given all the necessary info. E is the margin of error. You should know what sigma and z are. Look up z for a 99% CI in the z table.





Proportions has a minimum sample formula as well.

E=z\sqrt{\frac{pq}{n}}

You have all you need to find E.


Thank you, I figure the 1st one. I still confused about p and do i use 0.25 for q?

No, p+q=1. If p=.5, then what does q have to be?