Answer:
The average weight of the whole class is: 56.78kg
Explanation:
Given
[tex]\bar x_{boys} = 65[/tex]
[tex]n_{boys} = 45[/tex]
[tex]\bar x_{girls} = 45[/tex]
[tex]n_{girls} = 37[/tex]
[tex]\bar x_{teachers} = 70[/tex]
[tex]n_{teachers} = 5[/tex]
Required
The average of the whole class.
This requires that we calculate the population average
This is calculated as:
[tex]\mu = \frac{\sum n_i * \bar x_i}{\sum n}[/tex]
So, we have:
[tex]\mu = \frac{45 * 65+ 37*45+5*70}{45+37+5}[/tex]
[tex]\mu = \frac{4940}{87}[/tex]
[tex]\mu = 56.78[/tex]
