Question

Q.no.1 The number of cars crossing a certain bridge in a big city in 10 intervals of five minutes each was recorded as follows: J 3.18 25. 15, 18. 30. 20. 20. 12, 9. 16, 15. Calculate, () the arithmetic mean, (ii) the median and (ii(} the geometric mean.​

Answer 1

Given:

Given that, numbers of cars crossing a bridge is being recorded as  25, 15, 18, 30, 20, 20, 12, 9, 16, 15.

To find:

We have to find:

1) Arithmetic mean

2) Median

3) Geometric mean

Solution:

For our simplicity let us arrange the observation in ascending order i.e

9 12 15 15 16 18 20 20 25 30

1) Mean =  $\frac{Sum of observation}{Number of observation.}$

Now,

Sum of observation = 9+12+15+15+16+18+20+20+25+30=180

Number of observation = 10

Mean = 180/10 = 18

∴ Mean = 18

2) Median:

It is the middle most term. If it would be an odd term then the middle most term would be selected as the median but out no of observation is even so it is difficult to find the middle most term.

So for this two middle term are chosen and their average is found and that is called the median.

Middle term is  16 and 18

Average = $\frac{16+18}{2}$ = 34/2 = 17

∴ Median = 17