Bivariate Analysis: Chi-Square, Fisher, and McNemar Tests Flashcards

1
Q

What is a Chi-Square Test?

A

Nominal or Dichotomous Variable, compared across 2 discrete independent groups
HOMOGENEITY

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2
Q

What is a Fisher’s Exact Test?

A

Dichotomous variable, compared two discrete independent groups

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3
Q

What is a McNemar Test?

A

Dichotomous variable, compared across Matched Measurements in two discrete dependent groups
PRE/POST

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4
Q

What is the Chi-Square Test of Homogeneity

A

Applied to a nominal variable from two or more different groups/populations to determine whether frequency counts are distributed identically across the groups

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5
Q

If a nominal variable is dichotomous, it means what?

A

There are ONLY two options
ex. improved vs not improved

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6
Q

For the Chi-Square Test of Homogeneity, the H0 compared what?

A

H0 = Pt = Pc
Proportion of patients with specific outcome will be EQUAL between treatment and comparison group
COMPARING PROPORTIONS NOT means

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7
Q

A large X^2 value in a Chi-Square tests = statistically significant, what can increase the value of x^2?

A

The larger the difference in proportions = greater x^2

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8
Q

A Chi-Square test is ONE directional with an alpha of 0.05 and a df =1, what is the the critical value?

A

3.84

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9
Q

What are the requirements/details of the Fisher’s Exact Test?

A
  1. More conservative than x^2, less chance of a false positive
  2. For 2x2 tables ONLY
  3. N<20 or if there are <5 in one of the cells
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10
Q

What is the Chi-Square Test of Independence?

A

Applied to 2 nominal variables from one group/population to determine whether frequency counts are distributed in a manner that shows an association between the two variables

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11
Q

What does Independence mean?

A

One variable does not say anything about another variable

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12
Q

What is the H0 and HA of the Chi-Square Independence Test?

A

H0: No association
HA: Association

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13
Q

What are the parameters of the Chi Square Independence Test?

A
  1. ONE Population
  2. TWO Dichotomous Variables
  3. FREQUENCY = ASSOCIATION
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14
Q

What are the requirements/details of the McNemar Test?

A
  1. Dependent groups, paired data
  2. Dichotomous variables, 2x2
  3. Compare proportions between PAIRED data
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