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Advanced Data Analysis > Unit 3 > Flashcards

Unit 3 Flashcards

1
Q

What are examples of parametric tests?

A

-F ratio-test (Bartlett’s test)
-1 sample t-test
-Paired t-test
-2 sample t-test
-One-Way ANOVA
-Factorial DOE with one factor and one blocking variable

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2
Q

What are examples of non-parametric tests?

A

-Leven’s Test
-1 sample sign
-1 sample Wilcoxon
-Mann-Whitney test
-Kruskal-Wallies
-Mood’s median test
-Friedman test

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3
Q

How do you calculate the standard error of the mean (SEOM)?

A

Standard deviation / square root of sample size

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4
Q

What is the recommended minimum sample size for t-tests to run properly?

A

When sample sizes are greater than 30

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5
Q

When do you use a z-test?

A

When sample sizes are greater than 100

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6
Q

What does a One sample t-test do?

A

Assesses whether the sample (one sample) mean differs significantly from a particular value (Usually a theoretical value)

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7
Q

When is an independent sample t-test used?

A

When there are two means and two groups that are independent of one another

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8
Q

When is pooled independent t-tests used?

A

When equal variance is assumed

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9
Q

When is non-pooled independent sample t-tests used?

A

When unequal variance is assumed

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10
Q

When is paired t-tests used?

A

-Dependent data (related samples)
-Before and after experiments on the same dataset

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11
Q

What is the p-value for significance?

A

<0.05

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12
Q

What is the p-value for highly-significant?

A

<0.01

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13
Q

What is the p-value for very high level of significance?

A

<0.001

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14
Q

What is the probability of 5% significance of being wrong?

A

Less than 1 in 20 chance of being wrong

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15
Q

What is the probability of 1% significance of being wrong?

A

Less than 1 in 100 chance of being wrong

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16
Q

What is the probability of 0.1% significance of being wrong?

A

Less than 1 in 1000 chance of being wrong

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17
Q

What does a one-tailed directional hypothesis predict?

A

Predicts the nature of the effect of the independent variable on the dependent variable.

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18
Q

What is an example of a one-tailed directional hypothesis?

A

In whether the levels of pollution are significantly larger than a maximum threshold marked by legislation.

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19
Q

What does two tailed non-directional hypothesis predict?

A

-Predicts that the independent variable will have an effect on the dependent variable, but the direction of the effect is not specified

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20
Q

What is an example of a two tailed non-directional hypothesis?

A

Whether differences in temperature are significantly different either above or below a certain value

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21
Q

What does the left tail in a one tail hypothesis predict?

A

-Looks for a negative effect
-Whether there is a reduction in the number species / individuals etc

22
Q

What does the right tail of a one-tailed hypothesis predict?

A

-Looks for a positive effect
-Whether there is an increase in number of species/ individual etc.

23
Q

How is the significance level distributed in a two-tailed test?

A

-Half in left and right tail
-Left 0.025
-Right 0.025
-Makes two tailed tests less powerful than one-tailed t-tests

24
Q

How is Cohen’s effect size calculated?

A

CES = Mean difference (mean of group 1 - mean of group 2) / standard deviation

25
Q

What is cohen’s effect size (Cohen’s d)?

A

Is an effect size used to indicate the standardised difference between two means

26
Q

What does a larger cohen’s effect size indicate?

A

A stronger relationship between two variables

27
Q

What does a cohen’s effect of 0.2 indicate?

A

Small

28
Q

What does a cohen’s effect of 0.5 indicate?

A

Medium

29
Q

What does a cohen’s effect of 0.8 indicate?

A

Large

30
Q

What is a non-parametric equivalent to a one sample t-test?

A

Wilcoxon Signed Rank Test

31
Q

What would be an example of null hypothesis for a Wilcoxon Signed rank test?

A

The population median (n) is equal to the hypothesised median

32
Q

How do you calculate the confidence interval?

A

Standard Error of the mean * t-critical

33
Q

How do you calculate the standard error of the mean? (SEOM)

A

Standard deviation / square root of sample size (n)

34
Q

How do you find the t-critical value?

A

Using degrees of freedom and a t-table.

You get your degrees of freedom by n-1, or you minus 1 from the number of samples you have

35
Q

What are two tests that compare variances?

A

-Fisher’s test
-Levene’s test

36
Q

Why does the variance need to be compared?

A

-Before conducting parametric testing to ensure that the right assumptions are met

37
Q

Is Fisher’s test normal or non normal?

A

Normal
Works best on parametric data
-Can only assess variances of two groups

38
Q

Is Levene’s test normal or non-normal?

A

Non-normal
Used for non-parametric datasets
-Can assess variances of more than two groups

39
Q

How is variance calculated?

A

Standard Deviation^2

40
Q

What does this symbol mean?
<

A

Less than

41
Q

What does this symbol mean?
>

A

Greater than

42
Q

When is the p-value not significant?

A

P > 0.05
Greater than 0.05

43
Q

When is the p-value significant?

A

P < 0.05
Less than 0.05

44
Q

What a is method of comparison of two groups that are non-parametric?

A

Mann-Whitney U test

45
Q

What are the assumptions of the Mann-Whitney test?

A

-Data is independent random samples
-Data must be measured at least at the ordinal or continuous level

46
Q

How do you get a Man-Whitney test in SPSS?

A

-Analyse
-Nonparametric tests
-Independent samples
-Settings
-Choose tests

47
Q

What do you use for man whitney non-parametric if the distributions are not the same in SPSS?

A

-Non parametric tests
-Legacy dialogs
-2 independent samples

48
Q

What is the non-parametric version of a paired t-test?

A

-Wilcoxon matched pairs test

49
Q

When do you reject the H0 in a Wilcoxon matched pairs test?

A

-If (smaller) T value is lower than or equal to the critical value ( from T-tables)

50
Q

How do you perform Wilcoxon signed rank test in SPSS?

A

-Nonparametric tests
-One sample
-Settings
-Choose test

Advanced Data Analysis (5 decks)

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