Range & Interquartile Range Flashcards

All 6 cards in this deck

What is the formula for the range of a set of data?

Range $=$ largest value $-$ smallest value.

What is the formula for the interquartile range?

IQR $=$ upper quartile $-$ lower quartile.

Where are the lower and upper quartiles in an ordered list of $n$ values?

Lower quartile at position $\frac{n+1}{4}$, upper quartile at position $\frac{3(n+1)}{4}$.

e.g. $n = 23$ → 6th and 18th values

True or false? Three quarters of the data lies between the lower quartile and the upper quartile.

False. The middle 50% (half) of the data lies between them.

What is an outlier?

A value that is much larger or much smaller than the rest of the data.

What effect does one very large outlier have on the mean, the median and the range?

It increases the mean and the range a lot, but has little or no effect on the median.