variance of first 50 even natural numbers?

the measurements of the diameters (in mm) of the heads of 107 screws are given below:

diamter :- 1) 33-35 no of screws :- 1) 17

2) 36 - 38 2) 19

3) 39 - 41 3) 23

4) 42-44 4) 21

5) 45 - 47 5) 27

calculate variance and standard deviation.

variance of first n odd natural numbers and

variance of first n even numbers

For a group of 50 male worker, the mean and standard deviation of their weekly wages are Rs 63 and Rs 9 respectively and for a group of 40 female workers, the measures are respectively Rs 54 and Rs 6 . Find the standard deviation for combined group workers.

1 : the mean deviation of series a,a+d,a+2d.....,a+2n from its mean is

Ans--n(n+1)d/2n+1

2 : the standard deviation of data

X 1 a a^2........ a^n

F nC0 nC1 nC2.......nCn

Ans----((1+a^2)/2)^n - ((1+a)/2)^n

What is quartile deviation ?

Please explain briefly with example.

All the students of a class performed poorly in mathematics. Thr teacher decided to give grace marks of 10 to each of the students. which of the following statistical measures will not change even after the grace were given ?

a. mean

b. median

c. mode

d. variance

Ans is 4. variance

Please explain that why the median is changed .

Find r if 5_Pr=2 6_Pr-1

Find the mean deviation about the mean for the data

4, 7, 8, 9, 10, 12, 13, 17

Find the mean deviation about the median for the data.

If the coefficient of variation of a distribution is 45 percent and the mean is 12, then its standard deviation is

a. 5.2

b. 5.3

c. 5.4

d. n.o.t.

Please explain briefly.

Find the mean deviation about the median for the data.

13, 17, 16, 14, 11, 13, 10, 16, 11, 18, 12, 17

Find the mean deviation about the median for the data

Find mean and variance

classes 0-10 10-20 20-30 30-40 40-50

freqeuncies 5 8 15 16 6.

If aⁿ+bⁿ/ a^n-1+b^n-1 is the A.M between a and b, then find the value of n.

class- 1-10 11-20 21-30 31-40 41-50 51-60

freq. - 11 29 18 4 5 3

Let x₁,x₂,...,x_n be n observaions such that ∑x_i² = 400 and ∑x_i = 80, then a possible value of n is

a. 9

b. 12

c. 15

d. 18

Please explain briefly

please tell me wheather the 'cofficient of correlation' is the measurement of central tendency or variation

Distance between two parallel planes6x+3y+6z=24and4x+2y+4z+6=0is

{VERY URGENT}Two samples of 100 and 150 obsevations have means 15 and 16 and standrd deviation 3 and 4. Find their combined mean and standard deviation.

x₁=1, x₂=2, x₃=3, ......, x₁₀₀=100, x₁₀₁=101, x₁₀₂=102, x₁₀₃=103, x₁₀₄=104.

Mean deviation from the median of the fiven data is

a. 51/2

b. 26

c. 36

d. n.o.t.

Please explain briefly.

In how many ways can one select a cricket team of eleven from 17 players in which only 5 players can bowl if each cricket team of 11 must include exactly 4 bowlers?

what is the base of statics