Answer:
a) 4
b) 30
c) 8
Step-by-step explanation:
The range is the difference between the biggest and the smallest number. The biggest mark is 10, and the smallest mark is 6.
⇒ Range = 10 - 6 = 4
To calculate how many students are in the group, add the values in the frequency column:
⇒ Total number of students = 5 + 4 + 7 + 10 + 4 = 30
To calculate the mean mark of the group, multiply each mark by its frequency, add these up, then divide by the total number of students:
⇒ Mean Mark = [ (6 × 5) + (7 × 4) + (8 × 7) + (9 × 10) + (10 × 4) ] ÷ 30
= [ 30 + 28 + 56 + 90 + 40 ] ÷ 30
= 244 ÷ 30
= 8.1333333333...
= 8 (nearest whole number)
