Question

The mean of a sample of size 10 is 15. If the value of each item is doubled, the mean of the sample will be _______.

• A. 15
• B. 30
• C. 11
• D. 22

Answer 1

The correct option is B 30

Mean refers to the average amount in a given group of data. So arithmetic mean can be calculated by adding the first term and the last term of the series and then dividing the sum by 2. In the given series the first term 'a' is doubled and the last term 'b' is also doubled , so the

Mean = {(a+a)+ (b+b)} /2

= (2a+2b) /2

= 2 (a+b) /2

= 2 [ (a+b)/2}

Therefore, the mean is also doubled. So,if the mean was 15 then now it will be 30.