All MCQs

The coefficient of variation is commonly calculated as standard deviation divided by mean.
It supports relative variability comparisons across compatible positive scales.

The extreme value 100 strongly pulls the mean upward.
The median remains 4 and better represents the central cluster.

Asymmetry in the box or whiskers reflects unequal spread on the two sides.
This pattern may indicate a skewed distribution.

Aligned box plots reveal differences in medians, spreads, and potential outliers.
They are efficient when many groups must be compared.

The upper fence is Q3 plus 1.5 times the interquartile range.
Points beyond it are flagged for investigation, not automatically deleted.

The lower and upper edges of the box are Q1 and Q3.
Their distance is the interquartile range.

The box extends from the first to the third quartile.
The internal line marks the second quartile, which is the median.

Subtracting the mean centers the observation, and dividing by the standard deviation scales it.
The result is unitless and supports cross-scale comparison.

A z-score expresses distance from the mean in standard-deviation units.
Positive values lie above the mean, while negative values lie below it.

Skewness is named for the direction of the longer tail.
A left-skewed distribution has its extended tail on the low-value side.

Large high-end values pull the mean toward the right tail.
The median is less affected, so it often remains below the mean.

The range is calculated as maximum minus minimum.
It is simple but highly sensitive to extreme observations.