StatCrunch logo (home)

Report Properties
Owner: naweiss@sc
Created: Dec 14, 2010
Share: no
Views: 5665
Results in this report
Data sets in this report
Need help?
To copy selected text, right click to Copy or choose the Copy option under your browser's Edit menu. Text copied in this manner can be pasted directly into most documents with formatting maintained.
To copy selected graphs, right click on the graph to Copy. When pasting into a document, make sure to paste the graph content rather than a link to the graph. For example, to paste in MS Word choose Edit > Paste Special, and select the Device Independent Bitmap option.
You can now also Mail results and reports. The email may contain a simple link to the StatCrunch site or the complete output with data and graphics attached. In addition to being a great way to deliver output to someone else, this is also a great way to save your own hard copy. To try it out, simply click on the Mail link.
ES8 Report 06.4
Mail   Print   Twitter   Facebook

You can use StatCrunch to obtain a normal probability plot. To illustrate, we discuss the StatCrunch solution to Example 6.14 of your text. 


Example   Normal Probability Plots


Adjusted Gross Incomes    The Internal Revenue Service publishes data on federal individual income tax returns in Statistics of Income, Individual Income Tax Returns. A simple random sample of 12 returns from last year revealed the adjusted gross incomes, in thousands of dollars, shown in Data set 1. Construct a normal probability plot for these data, and use the plot to assess the normality of adjusted gross incomes.

Data set 1. Adjusted gross incomes ($thousands)   [Info]
To analyze this data, please sign in.

Solution   Proceed as follows.


1       Choose Graphics QQ Plot

2        Select the column AGI

3       Click Create Graph!

The output that you obtain should match that shown in Result 1. It provides the required normal probability plot of the data. Note that StatCrunch plots the sample data on the vertical axis and the normal quantiles (normal scores) on the horizontal axis.

Result 1: Normal probability plot for the sample of adjusted gross incomes   [Info]
Right click to copy

From Result 1, we see that the normal probability plot for the sample of adjusted gross incomes is curved, not linear. Evidently, last year’s adjusted gross incomes are not normally distributed.

·  ·  ·

Always Learning