.The frequency table below shows the marks obtained by some students in an English Assignment.

Marks

31 - 40

41 - 50

51 - 60

61 - 70

71 - 80

81 - 90

91 - 100

Number of Students

10

20

12

13

9

7

4

a.Copy the table above and construct the cumulative frequency column.

b.Using a scale of 2 cm to represent 10 marks on the x-axis and 1 cm to represent 5 students on

the y-axis draw the cumulative frequency graph by using the upper class boundaries.

[1+3+2+1+1 marks - scale, connected paths, label of axis, title, curve]

3c.Use your graph to find the:

i.median, upper and lower quartile.

ii.probability that a student scored at most 92 marks

iii.percentage of student who obtained a mark of 55 or less.

iv.If the top 20% of the class obtained distinction, what is the minimum mark that will

guarantee a student getting a distinction?