Question

Find the variance and standard deviation for the following data: | xi | 4 | 8 | 11 | 17 | 20 | 24 | 32 | |----|---|---|----|----|----|----|----| | fi | 3 | 5 | 9 | 5 | 4 | 3 | 1 |

Calculate the mean, variance and standard deviation for the following distribution : | Class | 30-40 | 40-50 | 50-60 | 60-70 | 70-80 | 80-90 | 90-100 | |-------|-------|-------|-------|-------|-------|-------|--------| | Frequency | 3 | 7 | 12 | 15 | 8 | 3 | 2 |