Question

(c) mean = 18.2, median = 18.3, standard deviation = 1
the coefficient of skewness is
this distribution is select

Explanation:

Step1: Recall skewness formula

The formula for the coefficient of skewness (using the relationship between mean, median and standard - deviation) is $Sk = 3\frac{\text{Mean}-\text{Median}}{\text{Standard Deviation}}$.

Step2: Substitute given values

We are given that $\text{Mean}=18.2$, $\text{Median}=18.3$ and $\text{Standard Deviation}=1$. Substitute these values into the formula: $Sk = 3\times\frac{18.2 - 18.3}{1}$.

Step3: Calculate the value

First, calculate the numerator: $18.2-18.3=- 0.1$. Then, multiply by 3: $3\times(-0.1)=-0.3$.

If the coefficient of skewness $Sk < 0$, the distribution is negatively skewed.

Answer:

The coefficient of skewness is $- 0.3$. This distribution is negatively skewed.