Week 4 - Statisitical Models Correlation & T-tests Flashcards

1
Q

It is critical in psychological research to operationalise key terms because…

A

The reader needs to know what is actually being studied

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2
Q

A normal distribution as a…

A

Bell shape

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3
Q

“It was predicted that individuals who completed more years of education would have lower cardiovascular disease burden”. What is the correct characterisation of this statement?

A

It is a directional hypothesis.

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4
Q

We use the terms independent variable and dependent variable for….

A

Experimental and quasi-experiential designs

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5
Q

We use the terms predictor variable and outcome variable in…

A

Observational

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6
Q

We are running a study manipulating bedroom light levels to investigate effects on sleep efficacy. What is the (1) IV and what is the (2) DV?

A

(1) bedroom light, (2) sleep efficacy

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7
Q

What is not a measure of central tendency?

a.
Skew

b.
Mean

c.
Median

d.
Mode

A

Skew

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8
Q

Leptokurtic means…

A

Positive kurtosis

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9
Q

Negative kurtosis is also …

A

Platykurtic

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10
Q

Normal distribution is also

A

Mesokurtic

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11
Q

when do we run a Spearman Correlation?

A

When the data is non parametric

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12
Q

When do we run a Wilcoxin test (as opposed to a t-tes)

A

when the DV is non paramtertic

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13
Q

We traditionally use cohens d to measure effec size for t-tests. True or False

A

True

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14
Q

a d-value of 0.2 is considered…

A

small effect

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15
Q

a d-value of 0.5 is considered…

A

moderate effect

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16
Q

a d-value of 0.8 is considered…

A

large effect

17
Q

Testing skew or kurtosis:
W statistic - maximum value of 1 = data looks perfectly normal
True or False

18
Q

Testing skew or kurtosis:
The smaller the value of W the less normal the data are?
True or false

19
Q

p value of W statistic
<.05 = non normal data
True or false

20
Q

p value of W statistic
>.05 = normal data
True or false

21
Q

p value of W statistic
>.05 = non normal data
True or false

22
Q

the higher the df = more statistical power
True or False

23
Q

df = participants - 1
True or false

24
Q

What are the assumptions of Pearson correlation?

A

Linear relationship (straight line).
Homogeneity of variance (homoscedasticity).
Parametric data/normality.
Independence.
At least one variable needs to be continuous.
The other variable can be continuous or dichotomous.

25
What are assumptions of t-tests?
Parametric data/normality. Independence. Homogeneity of variance (homoscedasticity). DV needs to be continuous. IV needs to be dichotomous (groups or time points
26
Pearson correlation r= 0 no relationship r=1 perfect positive relationship R -1 perfect negative relationship True or False
True
27
Pearson correlation also measures effect size -1.0 to- 0.9 is a very strong negative correlation -0.9 to -0.7 strong neg -0.7 to -0.4 moderate neg -0.4 to -0.2 is a weak negative correlation -0.7 to -0.4 is moderate negative 0 - 0.2 is a negligible positive 0.2 to 0.4 is a weak positive correlation 0.4 to 0.7 Moderate pos 0.7 to 0.9 is a strong pos 0.9 to 1.0 is a very strong positive correlation
True
28
Why do we use t-test
When you want to compare two means
29
When do we use between independent t-test?
If those two means are from different groups - assigned to 1 condition only i.e., group 1 vs group 2
30
When do we use within groups dependent/paired t-test?
if those two means are from the same people - assigned to both conditions i.e., time 1 vs time 2 using the same groups to compare
31
Parametric data (normal) Bell curve Not too skewed (sway left or right) Not too kurtotic (flat or peaky) No outliers (extreme values) T or F
True