A company has three establishments A,B and C in three cities. Analysis of the daily wages paid to the employees in the three establishments is given below:
| Establishments: | A | B | C |
| Number of employees: | 20 | 25 | 40 |
| Average daily wages: | 305 | 300 | 340 |
| Standard Deviation: | 50 | 40 | 45 |
Find the average and standard deviation of the wages of all the 85 employees in the company.
MEAN OF MONTHLY WAGES(A) = TOTAL WAGES / NO OF WORKERS
TOTAL WAGES (A) = MEAN (A) * NO OF WORKERS(A)
TOTAL WAGES (A) = 305 * 20 = 6100
IN THE SAME WAY,
TOTAL WAGES (B) = 300* 25 =7500
TOTAL WAGES (C) = 340 * 40 =13600
AND FOR STANDARD DEVIATION :
FOR A = √50
SAME B = √40 AND C = √ 45