Types of graphs and date

categorical, ranked, discrete numerical (countable), continuous numerical (range).

Box plot shows minimum, the quartiles, median and maximum.

Frequency polygon is a regular line graph. Cumulative frequency curve.

Histogram is bar chart for continuous data.

How to calculate a specific percentile

Percentile wanted x total frequency / 100

averages are referred to measures of central tendency.

Standard deviation and outliers

Standard deviation - deviation is value - mean. Square the deviations and then find the means of them for the range of values. Then square root.

Outliers are 1.5 x the interquartile range. either lower the lower quartile or over upper quartile. or 2 standard deviations away from the mean.

working with histograms

Frequency = frequency density × class width

Mean = frequency x midpoint / frequency