# Difference between revisions of "Segment 19. The Chi Square Statistic"

John Hawkins (talk | contribs) (Added class exercise and data file.) |
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The direct YouTube link is [http://youtu.be/87EMhmPkOhk http://youtu.be/87EMhmPkOhk] | The direct YouTube link is [http://youtu.be/87EMhmPkOhk http://youtu.be/87EMhmPkOhk] | ||

− | Links to the slides: [http:// | + | Links to the slides: [http://wpressutexas.net/coursefiles/19.ChiSquareStatistic.pdf PDF file] or [http://wpressutexas.net/coursefiles/19.ChiSquareStatistic.ppt PowerPoint file] |

===Problems=== | ===Problems=== | ||

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==== Class Exercise ==== | ==== Class Exercise ==== | ||

− | [http:// | + | [http://wpressutexas.net/coursewiki/images/3/39/Chi_square.pdf Class Exercise] |

Data file: [[Media:mv_chi.txt]] | Data file: [[Media:mv_chi.txt]] |

## Latest revision as of 14:37, 22 April 2016

#### Watch this segment

(Don't worry, what you see statically below is not the beginning of the segment. Press the play button to start at the beginning.)

{{#widget:Iframe |url=http://www.youtube.com/v/87EMhmPkOhk&hd=1 |width=800 |height=625 |border=0 }}

The direct YouTube link is http://youtu.be/87EMhmPkOhk

Links to the slides: PDF file or PowerPoint file

### Problems

#### To Calculate

1. Prove the assertion on lecture slide 5, namely that, for a multivariate normal distribution, the quantity , where is a random draw from the multivariate normal, is distributed.

#### To Think About

1. Why are we so interested in t-values? Why do we square them?

2. Suppose you measure a bunch of quantities , each of which is measured with a measurement accuracy and has a theoretically expected value . Describe in detail how you might use a chi-square test statistic as a p-value test to see if your theory is viable? Should your test be 1 or 2 tailed?

#### Class Exercise

Data file: Media:mv_chi.txt