Fid standard deviation, variance and coefficient of variation from the following data.
wage (in rupees) no.of person
Less than 10 |. 12
Less than 20 |. 30
Less than 30 |. 65
Less than 40 |. 107
Less than 50 |. 157
Less than 60 |. 202
Less than 70 |. 222
Less than 80 |. 230