2. A researcher intends to estimate the effect of a drug on the scores of human
ID: 3232280 • Letter: 2
Question
2. A researcher intends to estimate the effect of a drug on the scores of human subjects performing a task of psychomotor coordination. The members of a random sample of 9 subjects were given the drug prior to testing. The mean score in this group was 9.13, and the sample variance was 17.76. An independent random sample of 10 subjects was used as a control group and given a placebo prior to testing. The mean score in this control group was 15.13, and the sample variance was 27.72.
Assuming that the population distributions are normal with equal variances, find a 95% confidence interval for the difference between the population mean scores.
The confidence interval is
nothing less than<mu Subscript x Baseline minus mu Subscript yxyless than<nothing .
3. Suppose that a random sample of 126 graduate-admissions personnel was asked what role scores on standardized tests play in consideration of a candidate for graduate school. Of these sample members, 76answered "very important." Find a 95% confidence interval for the population proportion of graduate admissions personnel with this view.
Click the icon to view the standard normal distribution table.
The 95% confidence interval is from nothing to nothing .(Round to four
decimal places as needed
Explanation / Answer
2. The statistical software output for this problem is:
Two sample T confidence interval:
1 : Mean of Population 1
2 : Mean of Population 2
1 - 2 : Difference between two means
(with pooled variances)
95% confidence interval results:
Hence,
95% confidence interval will be:
(-28.84, 16.84) [Rounded off to 2 decimal places]
3. The statistical software output for this problem is:
One sample proportion confidence interval:
p : Proportion of successes
Method: Standard-Wald
95% confidence interval results:
Hence,
95% confidence interval will be:
(0.5177, 0.6886)
Difference Sample Diff. Std. Err. DF L. Limit U. Limit 1 - 2 -6 10.826607 17 -28.842145 16.842145Related Questions
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