The table shows the travelling time to work of 50 people.

-Travelling time (t)

in minutes-

0
10 < t < 20

20 < t < 30

30 < t < 40

40 < t < 50

-Frequency-

5

15

13

10

7

Calculate an estimate of the mean travelling time.

24.8 mins

Step-by-step explanation:

Time > timemark > frequency

0 - 10 > 10/2 = 5 > 5

10 - 20 > (10+20) / 2 = 15 > 15

20 - 30 > (20+30) / 2 = 25 > 13

30 - 40 > (30+40) / 2 = 35 > 10

40 - 50 > (40+50) / 2 = 45 > 7

The mean time for the 50 people is given by:

Mean = summation (mid time x frequency) / total frequency

Mean = [5x5 + 15x15 + 25x13 + 35x10 + 45x7] / 50

Mean = [25 + 225 + 325 + 350 + 315] / 50

Mean = 1240 / 50

Mean = 24.8 mins