Guyss... Pls help me out with this..
The algebraic sum of deviations of 100 observations measured from 50 is zero and sum of squares of deviations from 50 is 4900.Then the variance is: ???
(pls add the explaination too.. )
Answers
Step-by-step explanation:
Step 1: Calculate the Sample Mean
To calculate a mean (often referred to as an average), add the individual values of your sample together and divide by n, the total items in your sample. For example, if your sample includes five quiz scores and the individual values are 63, 89, 78, 95 and 90, the sum of these five values is 415, and the mean is therefore 415 ÷ 5 = 83.
Step 2: Subtract the Mean From the Individual Values
In the present example, the mean is 83, so this subtraction exercise yields values of (63-83) = -20, (89-83) = 6, (78-83) = -5, (95-83) = 12, and (90-83) = 7. These values are called the deviations, because they describe the extent to which each value deviates from the sample mean.
Step 3: Square the Individual Variations
In this case, squaring -20 gives 400, squaring 6 gives 36, squaring -5 gives 25, squaring 12 gives 144, and squaring 7 gives 49. These values are, as you would expect, the squares of the deviations determined in the previous step.
Step 4: Add the the Squares of the Deviations
To get the sum of the squares of the deviations from the mean, and thereby complete the exercise, add the values you calculated in step 3. In this example, this value is 400 + 36 + 25 + 144 + 49 = 654. The sum of the squares of the deviations is often abbreviated SSD in stats parlance.