Maths - Statistics

sum of numbers / total no of numbers

2,3,4,5,6

Mean = 2+3+4+5+6 /5

1.Arrange no's in ascending order.
2.If odd - center no
If even - average of middle two numbers.

1,2,3,4,5 median =3
1,2,3,4,4,5,6 median =4
2,2,3,4,5 median=3
even
1,2,3,4,5,6 median = 3+4/2
1,2,2,3,4,6 median = 2+3/2

The number which occurs highest number of times.
1,1,2,3,4,5,6 mode = 1
1,2,3,3,4,5,5 mode = 3 and 5

Difference (highest no)-(lowest no)

12,2,3,4,3,2,1 range = 12-1

1.Find the mean
2.Differnce of each no (x) from the mean
= (x-mean)
3.Squares of each difference
= (x-mean)^2
4. Average of all differences.

No of times a number occurs in the given set of numbers.

x 1 2 3 4 5 6
f 2 3 1 1 1 1

1.Mean 1*2+2*3+3*1+4*1+5*1+6*1/2+3+1+1+1+1 = r

2.Standard deviation
sumation(1-r)^2 *F/sumation F
then
1.find mean of all x numbers


2.Mean of the set of no is

If u add same number 5(or any other)to a set of numbers then

1.The new mean = old mean +no added

2.New median = old median + no added.

3.Standard deviation doesnt change
(as the range will have the same spread around a new center)

The spread of numbers 200 to 400 is about 300.So its avg is 300.
Similarly for 50 to 100 the spread is about 75.so avg is 75.
So difference in averages is 300-75 = 225.