Test Index

WAEC Further Mathematics 2020 Paper

Question : 30

Total: 39

\sqrt{2}

\sqrt{2}

\sqrt{2}

)

Solution:

Concept:

Variance measures the average of the squared deviations of each value from the mean.

Explanation:

First, find the mean of the three values:

\bar{x} = \frac{\sqrt{2} + (1+\sqrt{2}) + (2+\sqrt{2})}{3}

\bar{x} = \frac{3\sqrt{2} + 3}{3} = 1 + \sqrt{2}

Now subtract the mean from each value.

\sqrt{2} - (1+\sqrt{2}) = -1

(1+\sqrt{2}) - (1+\sqrt{2}) = 0

(2+\sqrt{2}) - (1+\sqrt{2}) = 1

Square these deviations and find their sum:

(-1)^2 + 0^2 + 1^2 = 2

There are 3 observations, so:

\text{Variance} = \frac{\sum (x - \bar{x})^2}{n} = \frac{2}{3}

Answer:

Variance

= \frac{2}{3}

, so the correct option is C.

Go to Question:

Prev Question

Next Question