Question

1) 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 9.42, and the sample variance was 17.31. 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 15.45, and the sample variance was 27.11. Assuming that the population distributions are normal with equal variances, find a 90% confidence interval for the difference between the population mean scores.

2) Supermarket shoppers were observed and questioned immediately after putting an item in their cart. Of a random sample of 290 choosing a product at the regular price, 210 claimed to check the price before putting the item in their cart. Of an independent random sample of 210 choosing a product at a special price, 161 made this claim. Find a 95% confidence interval for the difference between the two population proportions.

3) From a random sample of 6 students in an introductory statistics class that uses group-learning techniques, the mean examination score was found to be 79.96 and the sample standard deviation was 2.4. For an independent random sample of 9 students in another introductory statistics class that does not use group-learning techniques, the sample mean and standard deviation of the test scores were 74.38 and 8.7, respectively. Estimate with 99% confidence the difference between the two population mean scores; do not assume equal population variances.

please explain step by step and which table u have used and how u get to the result.

Answer 1