Question

The mean of 40 observations was 160. It was detected on rechecking that the value

of 165 was wrongly copied as 125 for computation of mean. Find the correct mean

(a) 161 (b) 159 (c) 166 (d) 111​

Answer 1

Answer:

a

Step-by-step explanation:

mean of 40 observations = 160

sum of 40 observations = 160×40 = 6400

actual sum = 6400-125+165 = 6440

mean = 6440/40 = 161

or

the change in mean = -125+165 /40 = 40/40= +1

actual mean = given mean + change in mean = 160+1 =161