I tried to make a post about this before and realized I didn’t provide enough information. Sorry about that! Here’s the updated version. I’m trying to complete my homework and am a bit ahead of the class on this in doing so. I can wait until the teacher goes over it in class but I’m kinda antsy at the same time. We’re relying on StatCrunch only in this class, but that program isn’t giving me the correct answer for one of the parts I need and I can’t understand what I need to do. My mind went blank on some steps from previous lessons.
A study was done on proctored and nonproctored tests. The results are shown in the table. Assume that the two samples are independent simple random samples selected from normally distributed populations, and do not assume that the population standard deviations are equal. Complete parts (a) and (b) below. Use a 0.01 significance level for both parts.
Group 1: n = 31 x̅ = 75.44 s = 10.05
Group 2: n = 35 x̅ = 81.69 s = 20.03
a. Test the claim that students taking nonproctored tests get a higher mean score than those taking proctored tests.
(This one I got correctly)H0: μ1 = μ 2H1: μ1 < μ2
The test statistic, t, is -1.64. (Round to two decimals as needed. I got this one correct.)
The P-value is .053 (Round to three decimals as needed. Also correct.)
Failed to reject because of insufficient evidence to support the claim.
Now I am told to construct a confidence interval for testing the claim. I have seen the example formulas, I have used a variety of online calculators, my math whiz (but not stats whiz) boyfriend to learn this on the spot to help piece it together. The calculators all give me different answers. I was able to do this for the first round of hypothesis testing with only one sample data, but I’m having complete issues with the two sample data.
I don’t need to be given the answer, just the baby steps on how to get there. =) Thanks guys! Sorry for the confusion of the previous post!