Question

a) Following are the marks obtained by 20 pupils of a class. Present the marks in frequency table and find the mean marks. 50, 90 70, 80, 50 40, 60, 40, 80, 50, 70, 70, 80 60, 40 70, 50, 70, 60, 70, ​

Answer 1

The frequency table organizes the marks into specific intervals with the corresponding number of occurrences, and the mean marks are calculated by summing all marks and dividing by the total number of pupils, resulting in a mean of 62.5.

Step-by-step explanation:

First, to present the marks in a frequency table, we organize the marks into intervals and count the number of occurrences (frequency) for each interval. Then, to find the mean marks, we calculate the sum of all the marks and divide by the total number of marks.

40-49: 3

50-59: 4

60-69: 3

70-79: 6

80-89: 3

90-99: 1

To calculate the mean, sum all marks: (3×40) + (4×50) + (3×60) + (6×70) + (3×80) + (1×90) = 120 + 200 + 180 + 420 + 240 + 90 = 1250. Now, divide by the total number of pupils, which is 20: 1250 / 20 = 62.5. Hence, the mean marks of the class are 62.5.

Answer 2

Represent the mark on frequency table as follows;

Marks Frequency

40 3

50 4

60 3

70 6

80 3

90 1

Mean= Sum of all the marks

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Frequency

(40×3)+(50×4)+(60×3)+(70×6)+(80×3)+(90×1)

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20

=2250

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20

=11.5