Question

The weekly wage of 1000 workers are normally distributed with a mean of rs.70 and a standard deviation of rs.5.estimation the lowest weekly wage of the 100 highest paid workers. solution

Answer 1

It says it is normal distribution which means the value of the wages follow the curve below. Mean is given as 70 INR so it represents the biggest vertical line in the centre.



SD is given as 5 INR so that just means that around 68.26% of workers have their wages between -5 to +5 of the mean (65-75 INR) and 95.44% between -10 to +10 of the mean (60-80 INR)
You want to know the number of workers getting more than 80 INR ..that is the region after second standard deviation (the portion that is represented from 2 in the graph above) which is 2.15% + .13% = 2.28%