Question

Study the following frequency distribution table.

xi 15 17 20 30 10 + f
fi 4 4 6 5 6
If the mean of the data is 18.8, then the value of f is
(A) 4 (B) 3 (C) 2 (D) 1
PLS ANSWER THIS AS QUICKLY AS POSSIBLE

Answer 1

Option C is correct.

f = 2

Explanation:

The mean is the sum of variables divided by the number of variables

Mean = (Σfx)/(Σf)

xi | 15 | 17 | 20 | 30 | 10 + f

fi | 4 | 4 | 6 | 5 | 6

Σfx = (15×4) + (17×4) + (20×6) + (30×5) + [(10+f)×6] = 60 + 68 + 120 + 150 + 60 + 6f = (458 + 6f)

Σf = 4 + 4 + 6 + 5 + 6 = 25

Mean = 18.8

18.8 = (458+6f) ÷ 25

458 + 6f = 25 × 18.8 = 470

6f = 470 - 458 = 12

f = (12/6) = 2

Hope this Helps!!!