Chi-Square Statistics Flashcards

1
Q

Data sets that are not contiguous. For example: Dead or alive, head injury or no head injury, cancer or no cancer, etc.

A

Categorical Variables

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2
Q

There is no mean,median, mode, or normal distribution for

A

Categorical data

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3
Q

Take on values that are names or labels

A

Categorical Variables

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4
Q

Different categorical variables can be associated with

-Ex: Is there a difference between college students and medical students in the number of hours of sleep per week?

A

Eachother

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5
Q

Categories may be inherent in the data or created by the researchers from

A

continuous data

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6
Q

We may want to change the data into categories if the categories are more clinically meaningful, or if the data are

A

Non-normally distributed

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7
Q

What is the conventional data presentation for the associations between categorical variables?

A

Contingency tables

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8
Q

In a contingency table, all data is independent, meaning that each person fits into only

A

1 box

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9
Q

What should we always do for contingency tables?

A

Put totals outside of each row/column

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10
Q

The appropriate statistic to use for categorical data

A

Chi-Square test

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11
Q

In the Chi-square test, we first want to establish categories and the determine the

A

Frequency within each category

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12
Q

Once we know the frequency within each category, we want to

A

Formulate a model

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13
Q

The last thing we want to do in our Chi square test is compare the normal to the expected to see if the categories are

A

Independent

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14
Q

The Chi squared test is written as

A

χ^2

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15
Q

Measure the observed frequencies and compares them to the expected

A

Chi-squared test

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16
Q

How do we calculate the expected values for each box on the contingency table?

A

Expected value = (row total x column total) / grand total

17
Q

For the chi-squared test, if our calculated value of X^2 is GREATER than the critical value, we

A

Reject the null hypothesis

18
Q

For the chi-squared test, if our calculated value of X^2 is LESS than the critical value, we

A

Can not reject null hypothesis

19
Q

The Chi-squared test is not valid for a 2x2 contingency table with very small samples. In this case, we use a

A

Fisher Exact Test

20
Q

In Chi-squared tests, we make the assumptions that the data are frequency data, there is an adequate sample size, and the measures are

A

Independent of eachother

21
Q

The study of disease occurence in human populations

A

Epidemiology

22
Q

Epidemiology also uses

A

Contingency tables

23
Q

Follow two groups of people, some who are exposed to a factor

A

Cohort studies

24
Q

Look at people with and without the disease and determine whether or not they were exposed

-like i the bone mineral example

A

Case-control studies

25
Q

Measures the odds of getting a disease, given an exposure, and compares that to the odds of getting the disease without it

A

Case-control study

26
Q

For a case-control study, we use the

A

Odds ratio (OR)

27
Q

When using the odds ratio, OR = 1 means

A

No difference in odds of exposure

28
Q

When using the odds ratio, OR > 1 means

A

The odds of getting the disease are increased w/ exposure

29
Q

When using the odds ratio, OR less than one

A

The odds of getting the disease decrease w/ exposure

30
Q

If the 95% confidence interval contains 1, than there is

A

No effect of the exposure

31
Q

Used when data is normally distributed, there are more than 2 groups, and each person can only fall into one of the groups (I.e. Married, divorced, single, etc.)

A

One way ANOVA

32
Q

Used when the data is normally distributed, and you want to do multiple tests on a single group (I.e. Taking blood pressure measurements at various times of the day.)

A

Multiple Measures ANOVA