For the data set: 5, 7, 9, 11, 13, the standard deviation is:

The mean of 40 observations was 34. Upon checking, it was found that two observations were wrongly copied as 4 and 7. If incorrect observations are replaced by the corrected values 11 and 13, then find the corrected mean.

The age distribution of 40 children is as follows

Consider the following statements in respect of the above frequency distribution.

(A) The median of the age distribution is 7 yr.

(B) 70% of the children are in the age group 6-9 yr.

(C) The modal class of the children is 8-9 yr.

Which of the above statements are true?

Choose the correct answer from the options given below:

The average of marks of 15 papers is 45. The average of marks of the first 8 papers is 48 and that of the last 8 papers is 40. The marks of the eight paper will be:

Read the information given in the table carefully and answer the question that follows:

NUMBER OF CALCULATORS SOLD BY SHOPS P, Q, R, & S IN JUNE, JULY AND AUGUST

(A) The difference between the total number of calculators sold by shops P and Q together in August and the number of calculators sold by shops R and S together in June is 42

(B) The average number of calculators sold by Shop S in the three months is 92

(C) The respective ratio between the total number of calculators sold by shops P and Q in July and the total number of calculators sold by shop Q in August is 45 : 31

Choose the correct answer from the options given below:

For the data 11, 15, 13, 12, 10, 8, 11, 7, 15, 11, 13, 7, 11, which of the following is true?

In a class of 30 students, 10 scored 40, 12 scored 50, 8 scored 60. The mean score is: