Question

Hi



if the mean of 5 observation x, x + 2, X + 4, x + 6, X + 8 is 13. find the value of x and hence find the mean of last three observations.

Answer 1

Hi there!

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What is Mean?

The average of a given set of numbers is called the Arithmetic mean, or simply the mean, of the given numbers.

Mean = $\frac{Sum \: of \: observations }{Number \: of \: observations }$

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For your solution to the given question refer to the attachment.

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Answer 2

Here is your solution

Given:-

The five observation are x, x + 2, X + 4, x + 6, X + 8 and their mean is 13

We have to find Value of x

Now

we know that

mean = Σxi/Σfi

=>13 = x + (x + 2) + (x + 4) + (x + 6) + (x + 8)/5

=>65 = 5x + 20

=>65 - 20 = 5x

=>45 = 5x

=>x = 9

The last three observation are:-

x+4=9+4=13

x + 6=9+6=15

X + 8=9+8=17

Now

mean of last three observation  = Σxi/Σfi

mean = 13 + 15 + 17/3

mean = 45/3

mean = 15

Hence

The value of x is 9.

The value mean of 3 last observation is 15.

Hope it helps you