# Z Scores, t-tests, 1-Way-ANOVA Flashcards Preview

## PS3021 Stats > Z Scores, t-tests, 1-Way-ANOVA > Flashcards

Flashcards in Z Scores, t-tests, 1-Way-ANOVA Deck (30)
1
Q

Briefly, what is the z-score?

A

Where all normal distributions are the same.

2
Q

How is the z-score calculated,

A

The mean is subtracted (so it equals 0) and that is divided by variance (so SD is 1).

3
Q

What is the main problem with z-scores?

A

They require us them know the sample parameters mean and SD.

4
Q

The t-distributions is (more/less) spread out then the z-distribution.

A

More.

5
Q

What does the spread of the t-distribution depend on?

A

The uncertainty of the estimates of the mean and SD.

6
Q

How is SEM directly calculated?

A

Use lots of sample estimates of the mean and calculate the variance.

7
Q

How is SEM indirectly calculated?

A

Divide the standard deviation of the sample by the square root of n.

8
Q

What is the main question in t test 1?

A

Is the sample mean the same as the hypothesised population mean?

9
Q

What is t in t test 1?

A

Distance between sample and hypothesised men’s divided by SEM.

10
Q

Why is a degree of freedom lost in t test 1?

A

Because an estimate of the sample mean is being used.

11
Q

What is the main question in t test 2?

A

Are the means of two samples the same?

12
Q

How is whether u1 = u2 assessed in t test 2?

A

Look at how many SDs data points are apart.

13
Q

How is t calculated in t test 2?

A

Using the standard deviations of the differences between the two means.

14
Q

What is generally used to assess and deal with homoscedasticity?

A

Levene’s test, then if p<0.05, use Satterwaithe’s correction.

15
Q

What is the main question in t test 3?

A

Is the mean difference of scores 0?

16
Q

How do all t tests express a difference between means?

A

As SEM: the number of SDs from the mean.

17
Q

Give 2 limits of t tests.

A

They assume normal distributions and they can only compare 2 means.

18
Q

In 1-way ANOVA, what is a direct estimate of the variance between means?

A

Calculate variance from the observed means.

19
Q

In 1-way ANOVA, what is an indirect estimate of the variance between means?

A

Calculate the SEM*2, which is the expected variance based on the spread of the individual data points about their mean.

20
Q

If an IV does not influence a DV, the direct and indirect estimate should be (the same/different).

A

The same.

21
Q

If an IV does influence a DV, the direct and indirect estimate should be (the same/different).

A

Different.

22
Q

In 1-way ANOVA, what makes up the observed value?

A

Grand mean + level effect + error.

23
Q

What is the sum of squares between?

A

The variability between level means (direct method).

24
Q

What is the error sum of squares?

A

The variability due to noice (indirect method).

25
Q

What ratio is ANOVA looking at?

A

The observed level effects to that expected from the error.

26
Q

What is effect size?

A

The proportion of total variability explainer by knowing which level data belongs to.

27
Q

What is R squared?

A

The proportion of variance explained in the experiment.

28
Q

A

The estimated proportion of variance in the population that level is likely to explain.

29
Q

In 1-way ANOVA, how is partial Eta-squared used?

A

To refer to the proportion of variance in the data explained by a factor of an interaction.

30
Q

In 1-way ANOVA, how is R squared used?

A

To refer to the promotion of variance explained by all factors and interactions.