The table shows the time 50 students spent on their homework.

time (t) in minuets frequency

0 ≤ t < 30 / 7

30 ≤ t < 60 / 27

60 ≤ t < 90 / 12

90 ≤ t < 120 / 4

work out an estimate for the mean time the students spent on their home work.

Answer: Mean = 52.8 mins

Step-by-step explanation:

We have lapses of 30 minutes, so we can write the average for each, this means that:

0 < t < 30 can be averaged to the middle of the range: 15 min.

Doing this, we have that:

7 students 15 min

27 students 45 min

12 students 75 min

4 students 105 min.

Now we can calculate the mean:

mean = (x1*n1 + x2*n2 + ...) / N

where x1 is the amount of time 1, and n1 is the number of students associated to that time and so on. N is the total number of students

Mean = (7*15min + 27*45min + 12*75min + 4*105min) / (7 + 27 + 12 + 4)

Mean = 52.8 mins