Chi square Flashcards

1
Q

parametrics stats assumptions

A

Sample is large enough
comes from normal distribution
homogeneity

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2
Q

What do we do when assumptions are not met?

A

Use non-parametric Statistics

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3
Q

Non-parametric Statistics

A
  • distribution free

- allows to analyze different data

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4
Q

Chi-Square X2

A

allows to determine if what you observe in a distribution is what would be expected by chance alone

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5
Q

number of dimensions

A

one sample:majors
two sample: majors by class year
Given no other information you expect categories to be equal

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6
Q

examples of when to use chi square

A

Gambling–> is it fair

criminal justice–> are police in wichita engaging in social profiling?

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7
Q

chi-square equation

A

X2 = ∑ (O-E)2/ E

X2 = Test statistic
O = Observed Frequency
E = Expected Frequency (By chance)

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8
Q

computing chi square

A

Null and Research Hypothesis (Words and Symbols)
Compute the Test Statistic
Determine if it is significant or not
Write a 2-3 sentence results section, including a numerical X2 statement.

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9
Q

hypotheses

A

Null hypothesis
H0: P1 = P2 = P3
Research hypothesis
H1: P1  P2  P3

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10
Q

Chi Square Example

A

Is the distribution of answers different than we would expect by chance?
Null Hypothesis: The responses not different than expected by chance
Research Hypothesis: The responses are different than expected by chance, reflecting some underlying preference

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11
Q

questions to ask ourselves

A

What’s our research question?
What’s our null hypothesis?
What’s our research hypothesis?

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12
Q

Table steps

A

Category/ O/E/D/(O-E)2/(O-E)2/E

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13
Q

Presenting Your Results (example)

A
x2(2) = 20.6, p < .05
x2  represents the test statistic
2 is the number of degrees of freedom
20.6 is the obtained value
p < .05 is the probability
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