Question

The following are the weights (in kg) of 8 students of a class : 50, 44.5, 48.7, 45.1, 50.4, 43, 51, 49.3.
(i) Find the mean weight.
(ii) If a teacher, whose weight is 62 kg, is also included then what will be the mean weight?

Answer 1

Mean weight of the students = 47.75

Mean weight after including teacher = 49.33

Explanation:

(i) Mean weight of the students = sum of terms / number of terms

= 50 + 44.5 + 48.7 + 45.1 + 50.4 + 43 + 51 + 49.3 / 8

=  382 / 8  

=  47.75

(ii) When teacher's weight is included, mean weight = sum of terms / number of terms

= 50 + 44.5 + 48.7 + 45.1 + 50.4 + 43 + 51 + 49.3 + 62 / 9

=  444 / 9  

=  49.33

Answer 2

Explanation:

i) The observations are :50,44.5,48.7,45.1,50.4,43,51,49.3

To find the mean weight :

Average = sum of all observations /total no. of observations.;

Average=50+44.5+48.7+45.1+50.4+43+51+49.3/8

=382/8

=47.7

ii) When one more observation is included then it becomes;

=382+62/9

=444/9

=49.3