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If \( \sum_{i=1}^{9}(x_i5)=9 \) and \( \sum_{i=1}^{9}(x_i5)^2=45 \), then the standard deviation of the \( 9 \) items \( x_1,x_2,โฆ,x_9 \) is_______
and
S.D.
The mean of a set \( 30 \) observations is \( 75 \). If each observation is multiplied by a nonzero number \( \lambda \) and then each of them is decreased by \( 25 \), their mean remains the same. Then \( \lambda \) is equal to _____
Let be observations.
Given,
Given
If the mean of the data: \( 7,8,9,7,8,7,\lambda ,8 \) is \( 8 \) then the variance of this data is ______
Variance,
The values of mean, median mode and mode coincide, then the distribution is________
In symmetric distribution
In a class of \( 100 \) students, there are \( 70 \) boys, whose average marks in a subject are \( 75 \). If the average marks of the complete class is \( 72 \), then what is the average marks of the girls?
Total students
Boys , Girls
Average marks of boys
But
Average marks of girls
Mean of the first \( ‘n’ \) numbers is _____
First numbers
Find the mean of the square of first \( ‘n’ \) numbers.
Mean
The mean age of \( 25 \) teachers in a school is \( 40 \) years. A teacher retires at the age of \( 60 \) years and a new teacher is appointed in his place. If how the mean age of the teachers in this school is \( 39 \) years, then the age of newly appointed teacher is ______
If the standard deviation of the numbers \( 2,3,a \) and \( 11 \) is \( 3.5 \), then which of the following is true?
Coefficient of variance \( =\dfrac{\cdots}{mean}\times100 \) solve it.
If the variance of the data is \( 121 \), then the standard deviation of the data is______
For an asymmetric distribution mode is equal to ______
For an asymmetric distribution
Find the mean deviation about the mean of the distribution.
Calculate the mean deviation about the mean deviation about the mean of the set of first \( n \) natural numbers when \( n \) is odd number.
Calculate the mean deviation about the mean of the set of first \( n \) natural numbers when \( n \) is an even.
Find the standard deviation of first \( n \) natural numbers.
Two sets each of \( 20 \) observations, have the same standard deviation \( 5 \). The first set has a mean \( 17 \) and the second mean \( 22 \). Determine the standard deviation of the set \( x \) obtained by combining the two sets.
The frequency distribution, where \( A \) is a positive integer, has a variance of \( 160 \). Determine the value of \( A \).
Find the standard deviation of the above frequency distribution.
There are \( 60 \) students in a class.
Determine the mean of the frequency distribution, where \( x \) is positive.
(image)
Determine the standard deviation of the frequency distribution.
The sum of \( 10 \) items is \( 12 \) and the sum of their squares is \( 18 \). The standard deviation is_____
The algebric sum of the deviation of \( 20 \) observations measured from \( 30 \) is \( 2 \). So, the mean of observation is ________
When tested the lives (in hours) of \( 5 \) bulbs were noted as follows: \( 1357,1090,1666,1494,1623 \). The mean of the lives of \( 5 \) bulbs is _______
If mode of a series exceeds its mean by \( 12 \), then mode exceeds the median by_______