Question

The following table shows the electricity (in units) used by 25 families of Eklara village in a month of May. Complete the table and answer the following questions.

Electricity used (units) xi	No. of Families (frequency) fi	fi×xi
30	7	.......
45	2	.......
60	8	.......
75	5	.......
90	3	.......
	N = .......	∑fixi =.......

(1) How many families use 45 units electricity?
(2) State the score, the frequency of which is 5.
(3) Find N, and ∑f_ix_i
(4) Find the mean of electricity used by each family in the month of May.

Answer 1

The following table shows the electricity (in units) used by 25 families of Eklara village in a month of May. Complete the table and answer the following questions.

Electricity used (units) xi	No. of Families (frequency) fi	fi×xi
30	7	30 × 7 = 210
45	2	45 × 2 = 90
60	8	60 × 8 = 480
75	5	75 × 5 = 375
90	3	90 × 3 = 270
	N = 25	∑fixi = 1425

(1) 2 families use 45 units electricity.

(2) The score with a frequency of 5 is 75.

(3) N = 25, and ∑f_ix_i = 1425

(4) Since,

$$\begin{gathered} \mathrm{Mean}=\frac{{\displaystyle \sum _{}}{f}_i{x}_i}{N} \\ =\frac{1425}{25} \\ =57 \end{gathered}$$

So, the mean of electricity used by each family in the month of May is 57.