The mean and standard deviation of 100 terms are 50 and 3, respectively. The sum of squares of the 100 terms is:
This problem requires us to find the sum of squares of 100 terms, given their mean and standard deviation. We will use the relationship between mean, standard deviation, and the sum of squares.
The formula for the mean ($\bar{x}$) is given by:
$$ \bar{x} = \frac{\sum x}{n} $$The formula for the variance ($\sigma^2$) is given by:
$$ \sigma^2 = \frac{\sum x^2}{n} - (\bar{x})^2 $$From this variance formula, we can rearrange it to solve for the sum of squares ($\sum x^2$):
$$ \frac{\sum x^2}{n} = \sigma^2 + (\bar{x})^2 $$ $$ \sum x^2 = n \left( \sigma^2 + (\bar{x})^2 \right) $$The sum of squares of the 100 terms is 2,50,900.
Calculate the mean from the following table.
Scores | Frequencies |
0-10 | 2 |
10-20 | 4 |
20-30 | 12 |
30-40 | 21 |
40-50 | 6 |
50-60 | 3 |
60-70 | 2 |
Find the standard deviation of the following data (rounded off to two decimal places).
5, 3, 4, 7
If the standard deviation of a population is 5, what will be its variance?
A. 10
B. 15
C. 25
D. 12.5
The variance of a set of data is 196. Then the standard deviation of the data is.
A. ± 14
B. 14
C. 96
D. 98The variance of a set of data is 144. Then the standard deviation of the data is:
A. ±12
B. 12
C. 44
D. 72