Two populations of students where tested for a score which is known to be normally distributed. The interest was in the

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Two Populations Of Students Where Tested For A Score Which Is Known To Be Normally Distributed The Interest Was In The 1 (46.41 KiB) Viewed 24 times

Two populations of students where tested for a score which is known to be normally distributed. The interest was in the difference between the means in the two populations. Towards this end two samples where conducted. At the first it was of size 15 , while at the second it was of size 17. The resulting means where 495 and 545 , with sampled standard deviations (S) 55 and 50 , respectively. (a) What is the pooled sampled variance? (b) Construct a two-sided 0.95 confidence interval for the difference between the mean, under the assumption of equal population variances, (c) Would you reject the null-hypothesis which says that the two means are identical versus the alternative which says that they are not? Use a significance level of 0.01 (d) Suppose two students, one from each population, are about to be sampled for their scores. What is a two-sided 0.95 prediction interval for the difference in their scores? Assume equal population variances. (e) Construct a 0.95 confidence interval for the ratio between the two population variances. Repeat but now for the population standard deviations.