# Guide to Excel for statistics

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## common statistical functions

• AVERAGE(cells) - arithmetical mean of cells specified
• MEDIAN(cells) - middle value; half the values are greater, half are less than the median
• COUNT(cells) - counts the number of values n; useful for standard error calculation
• VAR(cells) - variance of a sample population; variance = standard deviation squared
• STDEV(cells) - standard deviation of a sample population; measures how much values vary from the mean

You can type these functions straight into the cells starting with the equal sign, e.g. type =stdev(A1:A10). Capitalisation is not important. Replace "cells" in the above list with the cells to be used for the calculation. Cells can be specified by clicking or typing. You can specify a range of cells by stating the (top) left and the (bottom) right cell, e.g. type A1:A10 (10 cells) or A1:B10 (2x10cells). Alternatively, you can enumerate cells using the comma as separator, e.g. A1,A3,A5. If you want to prevent automatic change of the column or row when copying formulae, use the dollar sign, e.g. \$A1 will keep the column the same while A\$1 will prevent a change in the row number.

## evaluation of Excel for statistics

Read this excellent review of Excel for statistics on practicalstats.com.

The main arguments are summarised below:

• many of Excel's charts violate standards of good graphics, i.e. fancy but not good for science
• many statistical methods are not available, e.g. box plots, 2-way ANOVA with unequal sample size, nonparametric tests
• several procedures are misleading, e.g. confidence function
• distributions are not computed with precision (Excel only correct to 2nd digit)
• regression routines are incorrect for multicollinear data
• ranks of tied data are computed incorrectly