Practical 3
1. Two independent samplesfrom populations that are normally distributed produced the following statistics: for sample 1 the samplesize was 19, the sample mean was 34.2 and the sample standard deviation was 12.6. For sample 2, thesample size was 23, the sample mean was 49.1 and the sample standard deviation was 19.4. Assume thatpopulation variances are equal. Construct a 95% confidence interval for the difference between thepopulation means. (μ1−μ22. A number of students in aGrade 9 maths course at a particular high school were randomly divided into two groups. Theexperimental group received teaching according to the new curriculum while the control group did not.All the students were given a test of computational skill (out of a total of 5 points) after the course andthe results were as follows: for the experimental group, the sample size was 27, the sample mean was1.19 and the sample variance was 74. For the control group, the sample size was 25, the sample meanwas 3.54 and the sample variance was 80. Assume that population variances are equal. Construct a 99%
)