20 ANOVA Flashcards

(21 cards)

1
Q

What does ANOVA stand for?

A

Analysis of Variance

ANOVA is a statistical method used to compare means among three or more groups.

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2
Q

What are the two types of ANOVA mentioned?

A
  • One-factor ANOVA
  • Two-factor ANOVA

The type of experimental design determines the type of ANOVA performed.

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3
Q

What is the purpose of ANOVA?

A

To compare more than two groups and identify differences in their means

It extends the test for the difference between the mean of two groups.

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4
Q

What is a factor in the context of ANOVA?

A

A characteristic thought to influence the measured observations

A level is a value of the factor.

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5
Q

When should you use a one-factor ANOVA?

A

When there is one categorical independent variable and one quantitative dependent variable with at least three levels

It is used in a completely randomised design.

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6
Q

What are the hypotheses for ANOVA?

A
  • H1: µ1=µ2=µ3=…
  • H0: At least two means differ
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7
Q

What are the three key assumptions for one-way ANOVA?

A
  • Observations are independent and random
  • Population at each factor level is approximately normally distributed
  • Normal populations have a common variance
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8
Q

What are the title in the source table for all ANOVA tests?

A

Source, SS, v, MS, F

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9
Q

What is the formula for the Mean of Squares, MS?

A

MS=SS/v

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10
Q

What is the formula for the F ratio, F?

A

F=MS(B)/MS(E)

Mean squares between divided by mean squares error

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11
Q

What is a blocking factor in two-way ANOVA?

A

A second factor that places subjects into homogenous groups called blocks

It helps control for variability in the experimental design.

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12
Q

What is the significance level typically used in hypothesis testing for ANOVA?

A

5%

This level is commonly used to determine statistical significance.

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13
Q

True or false: ANOVA can only be performed with two groups.

A

FALSE

If there are onlt two groups to be tested, the two sample z or t test would be appropriate

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14
Q

What is the mean square (MS) in ANOVA?

A

The sum of squares divided by the degrees of freedom

It is used to calculate the F ratio.

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15
Q

What is the F ratio in ANOVA?

A

Mean square between groups divided by mean square within groups

This is used as the test statistic in an ANOVA

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16
Q

Fill in the blank: A level is a _______ of the factor.

A

value

Levels are specific values that a factor can take in an experiment.

17
Q

What is the total in ANOVA?

A

The overall sum of squares from all sources of variation

It includes both between-group and within-group variations.

18
Q

Which experimental design is associated with one-factor ANOVA?

A

Completely randomised design

19
Q

Which experimental design is associated with two-factor ANOVA?

A

Randomised block design

20
Q

How could you comment on any difference found in an ANOVA hypothesis test?

A

Calculate the mean of each level in the factor mentioned and compare these.

21
Q

How do you test if a blocking factor is effective?

A

Use the F ratio for the blocking factor and test against the CV for that factor, if the F ratio is significant then the blocking factor was effective