Simply Statistics

Mean- Mean is the average of a set of data points. This is calculated by adding up all of the data points in a set of data and then dividing that number by the number of data points in the set.

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Median- Median is the middle number of a set of data. If the data set has an even number of terms then the median is the average of the middle two terms of the data set. If the data set is has an odd number of terms then the median is just the middle number of the data set.

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Mode- The mode is the data point that occurs most frequently in a set of data.

Standard Deviation- The standard deviation can be calculated using the formula if it is a sample of data and  if it is a population of data.

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Variance- The variance can be calculated by squaring the standard deviation of a data set

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Range- The range can be calculated by subtracting the lowest data point from the highest data point.

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Percentiles- Percentiles represent how much of the data is below that certain point in the date. Thus, the twenty-fifth percentile measures where twenty-fiver percent of the data has been accounted for. The fiftieth percentile measure where fifty-percent of the data has been accounted for, and the seventy-fifth percentile is where seventy-five percent of the data has been accounted for.

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Quartiles- Quartiles are used primarily with box and whisker plots and measure twenty-five percent of the data set. So, the first quartile measures the first twenty-five percent of the data, the second quartile is the median of the data, or the fiftieth percentile, and the third quartile corresponds to the seventy-fifth percentile.