Question

For the distribution of scores on a certain statistics test is strongly skewed to the left, which of the statement is NOT correct?

A. There are approximately 68% of the data points fall into the range of +1 SD and -1 SD in this distribution

B. Mean < Median

C. Median and interquartile range are a set of measures more appropriate to describe the center and spread for the distribution.

D. All of them above

Answer 1

Solution :

We know that only for symmetric distributin 68% data lies in 1SD of mean hence it is not correct for Negatively skewed distribution. Hence Option A is NOT Correct.

for negatively skewed distribution Mean < Median < mode

Hence option B. Mean < Median is correct

Also for skewed distribution median is good estimator for centre point than mean. Hence option C is correct.

Hence Answer :

A. There are approximately 68% of the data points fall into the range of +1 SD and -1 SD in this distribution