RESEARCH METHODOLOGY

STATISTICAL TECHNIQUES AND TOOLS

MEASURES OF CENTER AND SPREAD

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
When a distribution is skewed to the left, ____
A
the mean is less than the median
B
the mean is greater than the median
C
the median is less than the mean
D
the mean and median are approximately equal
Explanation: 

Detailed explanation-1: -To summarize, generally if the distribution of data is skewed to the left, the mean is less than the median, which is often less than the mode. If the distribution of data is skewed to the right, the mode is often less than the median, which is less than the mean.

Detailed explanation-2: -A distribution is called skewed left if, as in the histogram above, the left tail (smaller values) is much longer than the right tail (larger values). Note that in a skewed left distribution, the bulk of the observations are medium/large, with a few observations that are much smaller than the rest.

Detailed explanation-3: -The mean of positively skewed data will be greater than the median. In a negatively skewed distribution, the exact opposite is the case: the mean of negatively skewed data will be less than the median. If the data graphs symmetrically, the distribution has zero skewness, regardless of how long or fat the tails are.

Detailed explanation-4: -The mean would be less than the median if the distribution is negatively skewed. In other words, the mean is less than the median when the distribution of scores is not symmetrical and there are more extreme scores in the bottom 50% than in the top 50%.

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