Question

The measurements (in mm) of the diameters of the heads of 50 screws are given below:

Diameter (in mm) (xi)	34	37	40	43	46
Number of screws (fi)	5	10	17	12	6

Calculate the mean diameter of the heads of the screws.

Answer 1

We know that,
Mean = $\frac{{\displaystyle \sum _{}{x}_i{f}_i}}{\sum _{}{f}_i}$

For the following data:

Diameter (in mm) (xi)	34	37	40	43	46
Number of screws (fi)	5	10	17	12	6

Mean = $\frac{\left(34\times 5\right)+\left(37\times 10\right)+\left(40\times 17\right)+\left(43\times 12\right)+\left(46\times 6\right)}{5+10+17+12+6}$
= $\frac{170+370+680+516+276}{50}$
= $\frac{2012}{50}$
= 40.24

Hence, the mean diameter of the heads of the screws is 40.24 .