Statistical Methods & Analysis MATH9875 Statistic/Procedure Quiz 1 Formulas Formula/Function “array” refers to the set of values in your sample or population 2k Rule “k” is equal to the number that makes 2k just greater than the number of observations Class Interval i = (maximum value – minimum value)/k Relative Frequencies =Class Total/Total Frequencies *100% Conditional Relative Frequencies =Cell Value/Marginal Value for the Condition *100% Arithmetic Mean =average(array) Median =median(array) Mode =mode(array) Weighted Mean =sumproduct(array of values, array of weights)/sum(array of weights) Coefficient of Skew =skew(array) Range =Max(array) – Min(array) Variance =var.p(array) or =var.s(array) Standard Deviation =stdev.p(array) or =stdev.s (array) Coefficient of Variation =standard deviation/mean x 100% Q1: i=0.25*n Q3: i=0.75*n Quartile Value Where i is the position of the data value. If i is not an integer, round up. If i is an integer, take the average of the data values in positions i and i+1 i=(p/100)*n Percentile Value Where i is the position of the data value. If i is not an integer, round up. If i is an integer, take the average of the data values in positions i and i+1 Interquartile Range (IQR) =Q3 – Q1 Upper Fence =Q3 + 1.5IQR Lower Fence =Q1 -1.5IQR Standardized Value (z-score) =(value - mean)/standard deviation