# What is the point estimate and 97% confidence interval?

• Dec 7th 2011, 07:20 PM
Genevieve03
What is the point estimate and 97% confidence interval?
Hi everyone. This is my first post on here. I have to do several problems similar to this on an upcoming exam and would really appreciate anyone explaining how I solve it. Thank you!

The mean annual earnings of pharmacists in the US are $230,000 and those of pediatricians to be$225,000. Suppose that these results are based on a random sample of 300 pharmacists and 400 pediatricians and that the population standard deviations are $28,000 and$32,000.

A.) What is the point estimate?
B.) Construct a 97% confidence interval for the mean difference between the mean annual earnings of pharmacists and pediatricians.
• Dec 7th 2011, 07:37 PM
pickslides
Re: What is the point estimate and 97% confidence interval?
Try $\displaystyle \bar{x}_1-\bar{x}_2\pm Z_{0.97}\times \sqrt{\frac{\sigma_1^2}{n_1}+\frac{\sigma_2^2}{n_2 }}$
• Dec 7th 2011, 08:53 PM
Genevieve03
Re: What is the point estimate and 97% confidence interval?
Thanks a lot pickslides. I have a big exam coming up so I really appreciate it!