Advertisements
Advertisements
प्रश्न
The mean of 100 observations is 40. It is found that an observation 53 was misread as 83.
Find the correct mean.
उत्तर
Given the mean of 100 observations is 40.
`(sumx)/n = barx`
⇒ `(sumx)/n = 40`
⇒ x = 40 x 100
⇒ x = 4000
Incorrect value of x = 4000
Correct value of x = Incorrect value of x - Incorrect observation + correct observation
= 4000 - 83 + 53
= 3970
Correct mean = `("correct value of" sumx)/n`
= `3970/100`
= 39.7
APPEARS IN
संबंधित प्रश्न
Find the mean of 43, 51, 50, 57 and 54.
Find the mean of the first six natural numbers.
In a series of tests, A appeared for 8 tests. Each test was marked out of 30 and averages 25. However, while checking his files, A could only find 7 of the 8 tests. For these, he scored 29, 26, 18, 20, 27, 24 and 29.
Determine how many marks he scored for the eighth test.
Find x if 9, x, 14, 18 x, x, 8, 10 and 4 have a mean of 11.
Find the mean of 75 numbers, if the mean of 45 of them is 18 and the mean of the remaining ones is 13.
If different values of variable x are 9.8, 5.4, 3.7, 1.7, 1.8, 2.6, 2.8, 8.6, 10.5 and 11.1;
find
(i) the mean ` barx `
(ii) the value of ` sum (x_i - barx)`
The mean of 5 numbers is 18. If one number is excluded, the mean of the remaining number becomes 16. Find the excluded number.
The mean of 16 numbers is 8. If 2 is added to every number, what will be the new mean?
The mean monthly salary of 10 members of a group is Rs.1,445, one more member whose monthly salary is Rs.1,500 has joined the group. Find the mean monthly salary of 11 members of the group.
If `bar"X"` is the mean of n observations x1, x2, x3,..., xn then the mean of `x_1/"a", x_2/"a", x_3/"a",...,x_"n"/"a" "is" bar"X"/"a"`, where a is an non-zero number.
i.e., if each observation is divided by a non-zero number, then the mean is also divided by it.
