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# Means Tests - PowerPoint PPT Presentation

Hypothesis Testing. Assumptions Testing (Normality). Means Tests. Normality Tests. Many Statistical Tests require normal data You must verify normality with a test. Testing for Normality. How do we test for normality?

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## PowerPoint Slideshow about 'Means Tests' - gauri

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Presentation Transcript

Testing

Assumptions

Testing

(Normality)

Means

Tests

Many Statistical Tests require normal data

You must verify normality with a test

How do we test for normality?

Compute the linear correlation coefficient between the sample data and normal scores

Normality Test

H0: (null hypothesis): data normally distributed

Ha: (alternative hypothesis): Data not normal

Normality Test

Test Statistic

P-value

Critical Value (Alpha ɑ) = ??

Compare p-value from test to specified significance level (alpha, α=0.05)

If the p-value is less than or equal to α=0.05, reject the null hypothesis,

Otherwise, do not reject (fail to) the null hypothesis

Normality Test

P-value: <0.01

Alpha (ɑ) = 0.05

Since p is < ɑ

Reject the null

hypothesis

Normality Test

Since we reject the null hypothesis

H0: (null hypothesis): data normally distributed

We accept the alternative hypothesis

Ha: (alternative hypothesis): Data not normal

…and determine that data are not normally

distributed