Calculate to two decimal accuracy?

Question

A survey of 254 randomly chosen residents in a city revealed that 4 had four tv sets, 22 has three sets, 83 has two sets, 140 had one set and 5 had no tv sets. Based on the survey. Calculate to two decimal accuracy:

What is the simple average of tv sets per household?

What is the weighted average tv sets per household?

Answer 1

If we ignore how many households (residents) had the various numbers of TV sets then the simple average is:

(4+3+2+1+0)/5=10/5=2 or 2.00 TV sets.

The weighted average would take into account how many households had each of the various numbers of TV sets. There are:

4×4+22×3+83×2+140×1+5×0=16+66+166+140+0=388 TV sets.

The number of households is 254, so the weighted average is 388/254=194/127=1.53 TV sets to 2 decimal places.

(Note that rounded to the nearest whole number, the weighted and simple averages are the same.)