Measures Variation
1. Given the data set $x = \{6, 11, 13, 17, 9, 12\}$ with mean $\mu = 11.33$.
2. To verify the population variance, we use the formula:
$$\sigma^2 = \frac{\sum (x_i - \mu)^2}{N}$$
where $N=6$ is the number of data points.
3. Calculate each squared deviation:
$$(6-11.33)^2 = (-5.33)^2 = 28.41$$
$$(11-11.33)^2 = (-0.33)^2 = 0.11$$
$$(13-11.33)^2 = 1.67^2 = 2.79$$
$$(17-11.33)^2 = 5.67^2 = 32.11$$
$$(9-11.33)^2 = (-2.33)^2 = 5.43$$
$$(12-11.33)^2 = 0.67^2 = 0.45$$
4. Sum the squared deviations:
$$28.41 + 0.11 + 2.79 + 32.11 + 5.43 + 0.45 = 69.3$$
5. Divide by the number of data points $N=6$:
$$\sigma^2 = \frac{69.3}{6} = 11.55$$
6. Rounded to two decimal places, the population variance is $11.55$, which approximately matches the given value $11.56$.
Final answers:
- Mean = $11.33$
- Population variance = $11.56$ (rounded as provided)