Question
Find the mean and variance for the following frequency distribution.
Classes |
0-10 |
10-20 |
20-30 |
30-40 |
40-50 |
Frequencies |
5 |
8 |
15 |
16 |
6 |
Solution
Class |
Frequency f_{i} |
Mid-point x_{i} | y_i - (X_i - 25)/10 | y_{i}^{2} | f_{i}y_{i} | f_{i}y_{i}^{2} |
0-10 |
5 |
5 |
–2 |
4 |
–10 |
20 |
10-20 |
8 |
15 |
–1 |
1 |
–8 |
8 |
20-30 |
15 |
25 |
0 |
0 |
0 |
0 |
30-40 |
16 |
35 |
1 |
1 |
16 |
16 |
40-50 |
6 |
45 |
2 |
4 |
12 |
24 |
50 |
10 |
68 |
Is there an error in this question or solution?
Solution Find the Mean and Variance for the Following Frequency Distribution. 0-10 10-20 20-30 30-40 40-50 Concept: Variance and Standard Deviation - Standard Deviation of a Discrete Frequency Distribution.