select the correct answer.\nwhat is the shape of the following distribution?\n{9, 10, 10, 11, 11, 12, 12…

select the correct answer.\nwhat is the shape of the following distribution?\n{9, 10, 10, 11, 11, 12, 12, 13, 13, 13, 14, 14, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 17, 17, 17, 17, 18, 19, 20}\na. negative skew\nb. positive skew\nc. symmetric\nd. asymmetric with no skew\ne. none of the above
Answer
Explanation:
Step1: Calculate the median
The data set has 30 values. The median is the average of the 15th and 16th - ordered values. The 15th value is 15 and the 16th value is 15, so the median is $\frac{15 + 15}{2}=15$.
Step2: Calculate the mean
The sum of the data values: $9+2\times10 + 2\times11+2\times12+3\times13+4\times14+4\times15+4\times16+4\times17+18+19+20$ $=9 + 20+22+24+39+56+60+64+68+18+19+20$ $=419$. The mean is $\frac{419}{30}\approx13.97$.
Step3: Analyze the skewness
Since the mean ($\approx13.97$) is less than the median (15), the distribution has a negative skew.
Answer:
A. negative skew