Theory question 105
Data PresentationThe table shows the marks scored by a group of students in a class test.
Mark: 0, 1, 2, 3, 4, 5
Frequency: 1, 4, 9, 8, 5, 3
(a)(i) Calculate the mean mark (ii) Find the median (b) If the information were to be represented in a pie chart, what would be the sectorial angle for the mark 2?
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Model answer
Total = 30 students.
(a)(i) Σfx = 0 + 4 + 18 + 24 + 20 + 15 = 81; mean = 81/30 = 2.7.
(ii) The 15th and 16th marks: cumulative 1, 5, 14, 22, so both are 3; median = 3.
(b) Angle = 9/30 × 360° = 108°.
Explanation
Sector angle = frequency ÷ total × 360°.