Theory question 110
Data Presentation(a) The distribution of junior workers in an illustration is as follows:
Clerks − 78
Drivers − 36
Typists − 44
Messengers − 52
Others − 30
Represent the above information by a pie chart.
(b) The table below shows the frequency distribution of marks scored by 30 candidates in an aptitude test.
Marks: 4, 5, 6, 7, 8, 9
No. of Students: 5, 8, 5, 6, 4, 2
Find the mean score to the nearest whole number.
Show the model answer
(a) Total = 78 + 36 + 44 + 52 + 30 = 240 workers, so each worker is 360°/240 = 1.5°
Clerks 117°, Drivers 54°, Typists 66°, Messengers 78°, Others 45° (total 360°)
Draw the circle, measure the sectors with a protractor and label each one.
(b) Σfx = 20 + 40 + 30 + 42 + 32 + 18 = 182; Σf = 30
Mean = 182 ÷ 30 = 6.07 ≈ 6
Sector angle = (number in group ÷ total) × 360°.