Chi Squared Flashcards

1
Q

What is chi squared?

A

An non-parametric inferential statistical test

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2
Q

What kind of data is involved?

A

Nominal data

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3
Q

What does it measure?

A

Tests whether or not a pattern of observations is statistically significant

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4
Q

How is degrees of freedom calculated?

A

n-1

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5
Q

What are the main assumption?

A
  • Nominal data
  • More than 20 observations
  • Cannot have 20% or more with exp. frequency <5
  • No category with exp. frequency <1
  • Frequencies, not percentages
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6
Q

What is the procedure

A
  1. Hypotheses
  2. Determine confidence level
  3. Calculate X squared
  4. Calculate degrees of freedom
  5. Determine significance level
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7
Q

What are observed values?

A

Frequency counts observed - one per category

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8
Q

What are expected values?

A

Frequency counts expected if H0 were true

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9
Q

If the sample represents the population what are we likely/unlikely to calculate?

A

Chi <1 is very likely

Chi >5 is very unlikely

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10
Q

If X squared exceeds the critical value, what happens next?

A

Move forward with the alternative hypothesis

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11
Q

Whats different about comparing samples?

A
  • Degrees of freedom
  • Expected values calculate for all categories in all samples
    ei = (total row*total column)/Grand total
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