Showing posts with label Solving Variables. Show all posts
Showing posts with label Solving Variables. Show all posts

Saturday, January 19, 2013

Solving Variables in Statistics


Introduction of solving variables in statistics

Statistics deals with the collection and analysis of numerical data. Statistics is specifically useful in drawing general conclusions about a set of data from a sample of the data. We can say  Statistics as descriptive statistics and analytical Statistics, Since it is describing the data and drawing conclusions from the data. Statistics can solves problems related to standard deviation, variance, mean, median, binomial coefficient,standard error parameter, sample size, variability coefficient and populations. Understanding What are Variables? is always challenging for me but thanks to all math help websites to help me out.

Formulae

Formulas for solving variables in statistics:

For solving mean m =  `(sum_(k=1)^nxx_(k))/n`
median is the number in the middle

For solving variance v =`(sum_(k=1)^n(x_(k)-m)^2)/(n-1)`
For solving standard deviation s =`sqrt(v)`
By solving the above formulas we get the result of the variables. Is this topic what is a rational number hard for you? Watch out for my coming posts.

Examples of Solving Variables in Statistics:

Now let us see some examples of solving variables in statistics.

How to find Mean?

Consider the series : 15, 18, 22, 20

Here n = 4

The sum : `sum_(k=1)^nx_(k)` =15+18+22+20

By substituting K=1 to 4 we get sum as 75

Mean m = `(sum_(k=1)^nxx_(k))/n` = `75/4`

The Mean or Average is 18.75

How to find Median?

Here take the variable median

Here we  have to take the series in order and there are two case available

Case 1:

Numbers in the series is odd

9, 3, 44, 17, 15

Line up your numbers(smallest to largest): 3, 9, 15, 17, 44

The number in the middle is 15

Median is 15

Case 2:

Numbers in the series is even

8, 3, 44, 17, 12, 6

Line up your numbers: 3, 6, 8, 12, 17, 44

Having 2 middles numbers

Add 8 and 12 and then divide by 2: 8+12 = 20 ÷ 2 = 10

The Median is 10.

How to find Variance?

Here take a variable variance

44,50,38,96,42,47,40,39,46,50

`(44+50+38+96+42+47+40+39+46+50)/10`

Mean m = 49.2

Variance v =`(sum_(k=1)^n(x_(k)-m)^2)/(n-1)` `= 2600.4/(10-1)`

The variance is 289

How to find Standard deviation?

Here take a variable standard deviation

The square root of variance is standard deviation =`sqrt(289)`

The standard deviation is 17