Question

selling price in $ frequency

12- 15 8

16-19 23

20-23 17

24-27 18

28-31 8

32-35 4

36-39 2

1.calculate the average selling price

2.calculate the median

3. construct a histogram

4. Describe the data

Answer 1

solution:

selling price frequency (F) mid point (M) FM   cumulative frequency

12-15 8 13.5 108 8

16-19 23 17.5     402.5 31

20-23 17 21.5 365.5 48

24-27 18 25.5 459 66

28-31 8 29.5 236    74

32-35 4 33.5 134 78

36-39 2 37.5 75     80

total 80 1780   

i) average selling price =

ii) median (m)= (N/2)th item = 80/2 = 40th item, which lies on the class interval 20-23

median = lower class +(m - lower cumulative freq.)/freq.*class interval

median =