Question

Let the sample mean of a set of 20 data points be 30. If it is discovered that a data point having value 25 was incorrectly entered as 15, what should be the revised value of the sample mean?​

Answer 1

Answer:

30.52

Step-by-step explanation:

First dataset mean= 30

finding sample mean eqn=(x1+x2+x3+.......x20)/19

by substituting this

(x1+x2+x3+.......x20)/19=30

from this 30*19=x1+x2+x3+.......x20

              570=x1+x2+x3+.......x20

x1+x2+x3+.......x20=570 (sum)

in this sum 25 was incorrectly entered as 15. so sum included the 15 in it

25-15=10

we have to add 10 to 570 to get actual sum

ie, 570+10=580

So revised value sample mean= 580/19=30.52