Advertisements
Advertisements
प्रश्न
If the mean of observations x, x + 2, x + 4, x + 6 and x + 8 is 11,
find:
(i) The value of x;
(ii) The mean of first three observations.
Advertisements
उत्तर
(i) Given that the mean of observations x, x + 2, x + 4, x + 6 and x + 8 is 11.
Mean = `"Observations"/n`
11 = `[ x + x + 2 + x + 4 + x + 6 + x + 8]/5`
11 = `[ 5x + 20 ]/5`
x = `35/5`
x = 7
(ii)The mean of first three observations are
= `[ x + x + 2 + x + 4 ]/3`
= `[ 3x + 6 ]/3`
= `[ 3 xx 7 + 6 ]/3` .....[ Since x = 7 ]
= `[ 21 + 6 ]/3`
= 9.
APPEARS IN
संबंधित प्रश्न
Find the mean of 43, 51, 50, 57 and 54.
Find the mean of the first six natural numbers.
Find the mean of the first ten odd 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 the mean of all factors of 10.
Find the mean of 75 numbers, if the mean of 45 of them is 18 and the mean of the remaining ones is 13.
The mean of 200 items was 50. Later on, it was discovered that two items were misread as 92 and 8 instead of 192 and 88.
Find the correct mean.
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 100 observations is 40. It is found that an observation 53 was misread as 83.
Find the correct mean.
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.
