Q8 of 108 Page 32

Mean, and standard deviation of 100 observations was found to be 40 and 10 respectively. If at the time of calculation two observations were wrongly taken as 30 and 70 in place of 3 and 27 respectively, find the correct standard deviation.

Given, Uncorrected mean is 40 and corrected SD is 10 and N = 100

To Find: Find the correct mean and SD


Explanation: Here,


Then,


The corrected sum of observation



So,




Variance =100



10000+160000


Incorrect


Correct


Correct


Correct SD,


Correct SD,


Hence, SD = 10.24


More from this chapter

All 108 →
6

Find the mean and variance of frequency distribution given below:

 7

The weight of coffee in 70 jars is shown in the following table:


Determine the variance and standard deviation of the above distribution.

 9

While calculating the mean and variance of 10 readings, a student wrongly used the reading of 52 for the correct reading 25. He obtained the mean and variance as 45 and 16 respectively. Find the correct mean and the variance.

 10

Calculate the mean, variance and standard deviation of the following frequency distribution: