Computer Tools

We can compute the statistical quantities we have seen before using a variety of computer tools.

Spreadsheets

Excel and Google Sheets usually have identical functions and syntax

• AVERAGE
• PERCENTILE
• PERCENTRANK
• NORMDIST

Python

• numpy.mean
• numpy.percentile
• numpy.histogram
• matplotlib.hist

Similar functions are also available in the Pandas python library.

R

• mean
• quantile
• percent_rank
• hist
• Normal Distribution

Spreadsheet Histograms

Plotting a histogram in Google Sheets

Spreadsheet Normal Distribution

We can plot a normal distribution in Google Sheets using the NORMDIST function.

For example, we can create a column of values of the data for the x-axis, a cell for the mean, and a cell for the standard deviation. We can then create a column of values of the distribution.

=NORMDIST(x-value, mean, standard devation, FALSE)

Note, the FALSE is so that you get the distribution function instead of the cumulative distribution function.

Sending Data to the Function

Most of the functions above require many numbers to calculate the answer so we need to send several numbers to the spreadsheet.

In many computer programs (Excel, Google Sheets, Python, R) you have a function name followed by parentheses and the numbers sent to the function are in the parentheses.

• =AVERAGE(range of numbers)

In excel, we specify a range of numbers by the cells where the data starts and ends. For example A1:A10 is all the numbers stored between cells A1 and A10. To select an entire column, we use the idiom A:A.

To calculate the average of these numbers, we type

=AVERAGE(A1:A10)

Selecting data from another sheet in the spreadsheet

Often our data is in another sheet in the spreadsheet. Here is a function to calculate the average of that data.

=AVERAGE(datasheet!A1:A10)

• = means do a function
• AVERAGE is the computer command
• datasheet is the name of the sheet with the data
• A1:A10 is the chunk of data,