Question

3 mark question. so, explain it breaf​

Answer 1

Answer:

52.5

Step-by-step explanation:

Okay, so first let's change the class column given here because here in the question the class is the cumulative frequency which is not really needed for finding mean. So let's change it to the class intervals and on changing what we get is :

Class                 Frequency($f_{i}$)     $x_{i}$          $f_{i} x_{i}$

0-20                       15                   10         150

20-40               (37-15)=22           30        660

40-60               (74-37)=37           50        1850

60-80              (99-74)=25           70        1750

80-100             (120-99)=21           90       1890

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        Total:           120                               6300

Now, using Direct Mean Method:

Σfixi / Σfi = 6300/120 = 105/2 = 52.5

Hence, mean of the given data is 52.5