Answer the following : The mean height of 200 students is 65 inches. The mean heights of boys and girls are 70 inches and 62 inches respectively and the S.D. are 8 and 10 respectively. Find the number of boys and the combined S.D.

Answer the following : The means ans S.D. of weights and heights of 100 students of a school are as follows. Which shows more variability, weights or heights?

Answer the following : The mean and S.D. of a group of 50 observation are 40 and 5 respectively. If two more observations 60 and 72 are added to the set, find the mean and S.D. of 52 items.

Answer the following : Given below the frequency distribution of marks obtained by 199 students. Compute arithmetic mean and S.D.

In a city there are two factories A and B. Each factory produces sports clothes for boys and girls. There are three types of clothes produced in, both the factories type I, II and III. For boys the number of units of types I, II and III are 80, 70 and 65 in factory A and 85,65 and 72 in factory B. For girls the number of units of I, II and III are 80, 75,90 in factory A and 50,55,80 in factory B. Express this information in terms of matrices and using matrix Algebra, answer the following question.(I) What is the total production of each type for boys and girls?