Markos27
11-22-2009, 09:45 PM
i, I've been trying to do thee for the past few hours and I'm just lost. I don't just want aswers, I really just need to e pointed in th right direction.
1. suppose psychiatrists use a certain reliable test to diagnose depression in patients. Non-depressed people taking the test score a mean of 10.21 points, but the population variance is unknown. A group of 21 patients diagnosed with depression took the test and scored a mean of 22.12 with a std. dev. of 10.73. The standard error was 2.34. Test the null hypothesis that the patients scored equal to or less than the non-depressed population with alpha of 0.05.
i'm really confused as to what test to run and I don't know how to test the hypothesis without the population SD and with standard error.
then I had to questions where i simply computed mean : #5
The data presented below are beta-endorphin levels for a sample of 10 patients 12 hours before surgery.
8.6, 15.1, 10.2, 2.9, 8.7, 11.3, 12.1, 6.5, 9.2, 11.4
Compute the average beta-endorphin level of those patients.
and: #6
The beta-endorphin levels of these SAME 10 patients are taken again 10 minutes before surgery. The data follows.
15.4, 27.9, 8.5, 20.3, 21.3, 22.9, 19.2, 25.4, 23.6, 14.1
What's the average beta-endrophin level now?
those were fine, but i posted them because the next ?'s relate to them and I was not sure how to do them.
Based on the results you got from questions 5 and 6, what can you conclude about the relationship between beta-endrophin levels 12 hours and 10 minutes before surgery? Verify your conclusion with a two-tailed t-test. Include your statistical hypotheses and the critcal t for alpha of 0.05.
and lastly:
here is another thought about the last question. Compute a 95% confidence interval of the averaged beta-endorphin level difference between the two samples above. Try to use the confidence interval to demonstrate your conclusion again.
any help would be greatly appreciated, this class has me so confused and stressed. I've taken high level math classes before, but with stats i just never understand the wording or when to use z test vs t test. i just don't get the concepts i think.
1. suppose psychiatrists use a certain reliable test to diagnose depression in patients. Non-depressed people taking the test score a mean of 10.21 points, but the population variance is unknown. A group of 21 patients diagnosed with depression took the test and scored a mean of 22.12 with a std. dev. of 10.73. The standard error was 2.34. Test the null hypothesis that the patients scored equal to or less than the non-depressed population with alpha of 0.05.
i'm really confused as to what test to run and I don't know how to test the hypothesis without the population SD and with standard error.
then I had to questions where i simply computed mean : #5
The data presented below are beta-endorphin levels for a sample of 10 patients 12 hours before surgery.
8.6, 15.1, 10.2, 2.9, 8.7, 11.3, 12.1, 6.5, 9.2, 11.4
Compute the average beta-endorphin level of those patients.
and: #6
The beta-endorphin levels of these SAME 10 patients are taken again 10 minutes before surgery. The data follows.
15.4, 27.9, 8.5, 20.3, 21.3, 22.9, 19.2, 25.4, 23.6, 14.1
What's the average beta-endrophin level now?
those were fine, but i posted them because the next ?'s relate to them and I was not sure how to do them.
Based on the results you got from questions 5 and 6, what can you conclude about the relationship between beta-endrophin levels 12 hours and 10 minutes before surgery? Verify your conclusion with a two-tailed t-test. Include your statistical hypotheses and the critcal t for alpha of 0.05.
and lastly:
here is another thought about the last question. Compute a 95% confidence interval of the averaged beta-endorphin level difference between the two samples above. Try to use the confidence interval to demonstrate your conclusion again.
any help would be greatly appreciated, this class has me so confused and stressed. I've taken high level math classes before, but with stats i just never understand the wording or when to use z test vs t test. i just don't get the concepts i think.