Essential theory Flashcards by D E

Choice of statistic, or statistical test, depends
on 4 things

What are they?

Scale of measurement
Research aims
Experimental design
Properties of dependent/outcome variable

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What are the 3 types of research aims?

Descriptive only
Relational (correlation)
Experimental (differences)

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What type of test do we use for normally distributed data?

Parametric

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What type of test do we use for not normally distributed data?

Non-parametric

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What 3 things do we look for in an experiment based on its experimental design?

Subjects design (between or within)
Number of independent variables (IVs)
Number of IV levels

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What are the 4 types of scales of measurement?

Nominal
Ordinal
Interval
Ratio

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Nominal
Ordinal
Interval
Ratio

These are…?

Scales of measurement

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Which scales of measurement are used for categorical data?

Nominal

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Which scales of measurement are used for discrete or continuous data?

Ordinal
Interval
Ratio

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What is nominal data?

Numbers or names serve as labels but no numerical relationship between values

e.g. gender, political party, religion

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Numbers or names serve as labels but no numerical relationship between values

e.g. gender, political party, religion

This is known as…?

Nominal data

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What is ordinal data?

Data is organised by rank

Values represent true numerical relationships but intervals between values may not be equal

e.g. race position, likert scale ratings

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What is interval data?

True numerical relationships and intervals between values are equal but scale has not true zero point

e.g. temperature (ºF), shoe size

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What is ratio data?

True numerical relationships, equal intervals and true zero point

e.g. height, distance

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Data is organised by rank

Values represent true numerical relationships but intervals between values may not be equal

e.g. race position, likert scale ratings

This is known as…?

Ordinal data

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True numerical relationships and intervals between values are equal but scale has not true zero point

e.g. temperature (ºF), shoe size

This is known as…?

Interval

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True numerical relationships, equal intervals and true zero point

e.g. height, distance

This is known as…?

Ratio

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A study’s research aim is to describe

What descriptive statistics should be used?

Summarise a set of sample
values

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What research aim does not allow us to make predictions and infer causality?

The research aim to describe

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What are the 2 statistics used in a study following the research aim of describing?

Central tendency
Spread

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What are the 3 types of measure of central tendency?

Mean
Median
Mode

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What are the 2 types of measure of spread?

Standard deviation
Range

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When do we use the mean as a measure of central tendency?

When data is:
- Discrete or continuous
- Normally distributed

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When data is:
- Discrete or continuous
- Normally distributed

We use…?

a. Mode
b. Mean
c. Median

b. Mean

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When do we use the median as a measure of central tendency?

When data is: - Discrete or continuous - Not normally distributed

When data is: - Discrete or continuous - Not normally distributed We use...? a. Mode b. Mean c. Median

c. Median

When do we use the mode as a measure of central tendency?

When data is categorical

When do we use standard deviation as a measure of spread?

When data is: - Discrete or continuous - Normally distributed

When data is: - Discrete or continuous - Normally distributed We use...? a. Standard deviation b. Range

a. Standard deviation

When do we use range as a measure of spread?

When data is: - Discrete or continuous - Not normally distributed

When data is: - Discrete or continuous - Not normally distributed We use...? a. Standard deviation b. Range

b. Range

Relational research explore ...?

The relationship between observed behaviours or phenomena

True or False? Relational research actively manipulate variables

False Nothing is actively manipulated in relational research

What type of research aim allows us to make predictions but not infer causality?

Relational research

Explores relationship between observed behaviours or phenomena a. Describe b. Infer differences c. Infer relationships

c. Infer relationships

Summarise a set of sample values a. Describe b. Infer differences c. Infer relationships

a. Describe

Examines the influence of one or more variables (IVs) on other variables (DVs) a. Describe b. Infer differences c. Infer relationships

b. Infer differences

Experimental research examines ...?

The influence of one or more variables (IVs) on other variables (DVs)

We cannot make predictions or claims of causality a. Describe b. Infer differences c. Infer relationships

a. Describe

We can make predictions but not claims of causality a. Describe b. Infer differences c. Infer relationships

c. Infer relationships

We can make predictions and claims of causality if confounding variables are controlled for a. Describe b. Infer differences c. Infer relationships

b. Infer differences

True or False? We can always make claims about causality regardless of whether we have controlled for confounding variables

False We can only make claims about causality IF we have controlled for confounding variables

How does experimental research control for confounding variables? List 2 ways

1. Random allocation (between-subjects) 2. Counterbalancing (within-subjects)

When is controlling for confounding variables not possible?

Quasi-experimental design

What type of research manipulates a small number of variables to measure the effect of the manipulated variables? a. Descriptive b. Relational c. Experimental

c. Experimental

What is an IV?

Hypothesised to influence the DV

The IV is measured on a ____ scale a. Categorical b. Discrete c. Continuous

a. Categorical

What is a DV?

Hypothesised to be ‘dependent’ on the IV

The DV is measured on a ____ scale a. Categorical b. Discrete c. Continuous

b. Discrete c. Continuous

Why do we measure the DV under different levels of the IV?

To determine the effect of the IV

How do we determine the effect of the IV?

We measure the DV under different levels of the IV

List 2 characteristics of true-experimental IVs

1. IVs are actively manipulated 2. Random allocation is possible (can make claims about causality)

List 2 characteristics of quasi-experimental IVs

1. IV reflects fixed characteristics 2. Random allocation is not possible (must be cautious about implying causality)

IVs are actively manipulated This applies to...? a. True experimental IVs b. Quasi-experimental IVs

a. True experimental IVs

IV reflects fixed characteristics This applies to...? a. True experimental IVs b. Quasi-experimental IVs

b. Quasi-experimental IVs

Random allocation is possible (can make claims about causality) This applies to...? a. True experimental IVs b. Quasi-experimental IVs

a. True experimental IVs

Random allocation is not possible (must be cautious about implying causality) This applies to...? a. True experimental IVs b. Quasi-experimental IVs

b. Quasi-experimental IVs

Handedness (2 levels: right, left) is an example of a...? a. True experimental IV b. Quasi-experimental IV

b. Quasi-experimental IV

Treatment group (3 levels: placebo, drugs, counselling) is an example of a...? a. True experimental IV b. Quasi-experimental IV

a. True experimental IV

Sport context (2 levels: solo, competitive) is an example of a...? a. True experimental IV b. Quasi-experimental IV

a. True experimental IV

Age (3 levels: 18-20yrs, 20-22yrs, 22-24yrs) is an example of a...? a. True experimental IV b. Quasi-experimental IV

b. Quasi-experimental IV

Distribution of participants across IV levels is known as...?

Subjects design

What is subjects design?

Distribution of participants across IV levels

Participants exposed to only one IV level a. Between-subjects (Independent Groups) b. Within-subjects (Repeated Measures) c. Mixed

a. Between-subjects (Independent Groups)

Participants exposed to all IV levels a. Between-subjects (Independent Groups) b. Within-subjects (Repeated Measures) c. Mixed

b. Within-subjects (Repeated Measures)

At least one IV is between subjects AND at least one IV is within subjects a. Between-subjects (Independent Groups) b. Within-subjects (Repeated Measures) c. Mixed

c. Mixed

Intervention vs. control group a. Between-subjects (Independent Groups) b. Within-subjects (Repeated Measures) c. Mixed

a. Between-subjects (Independent Groups)

Sober vs. drunk a. Between-subjects (Independent Groups) b. Within-subjects (Repeated Measures) c. Mixed

b. Within-subjects (Repeated Measures)

At the end of Year 1, Year 2 and Year 3 of Uni a. Between-subjects (Independent Groups) b. Within-subjects (Repeated Measures) c. Mixed

b. Within-subjects (Repeated Measures)

Teachers vs. accountants vs. nurses a. Between-subjects (Independent Groups) b. Within-subjects (Repeated Measures) c. Mixed

a. Between-subjects (Independent Groups)

An investigator is interested in whether right and left-handed people differ in their performance on different types of computer-games (his theory is that left-handed people will have an advantage on games requiring better visuo-spatial skills). He measures the scores of 30 right handers and 30 left handers who each play Daley Thompson’s Decathlon, Horace Goes Skiing & Tetris What is the...? a. IV(s) b. IV(s) levels c. DV d. Subjects design

a. Handedness, Games b. 2 (right and left), 3 (Decathlon, Horace and Tetris) c. Performance on computer games d. Mixed

What analysis do you perform on an experimental study with 1 IV and 2 levels and participants are exposed to only one IV level?

Independent t-test

What analysis do you perform on an experimental study with 1 IV and 2 levels and participants are exposed to all IV levels?

Paired t-test

What analysis do you perform on an experimental study with 1 IV and more than 2 levels and participants are exposed to only one IV level?

One-way independent ANOVA

What analysis do you perform on an experimental study with 1 IV and more than 2 levels and participants are exposed to all IV levels?

One-way repeated measures ANOVA

What analysis do you perform on an experimental study with 2 IVs and participants are exposed to only one IV level?

Two-way independent ANOVA

What analysis do you perform on an experimental study with 2 IVs and participants are exposed to all IV levels?

Two-way repeated measures ANOVA

What analysis do you perform on an experimental study with 2 IVs and participants are exposed to all IV levels for one IV and only one level for the other IV?

Two-way mixed ANOVA

What are the properties of normal distribution? List 2

1. Symmetrical about the mean 2. Bell shaped (suggests majority of the scores cluster close to the mean)

What are the 3 types of kurtosis?

1. Mesokurtic 2. Platykurtic 3. Leptokurtic

Which kurtosis can we use for parametric statistics? a. Mesokurtic b. Platykurtic c. Leptokurtic

a. Mesokurtic

Which kurtosis can we use for non parametric statistics? a. Mesokurtic b. Platykurtic c. Leptokurtic

b. Platykurtic c. Leptokurtic

Which kurtosis is used when data is normally distributed/bell shaped? a. Mesokurtic b. Platykurtic c. Leptokurtic

a. Mesokurtic

Which kurtosis is used when data is more varied (the distribution peak is flatter and peak at the mean is lower? a. Mesokurtic b. Platykurtic c. Leptokurtic

b. Platykurtic

Which kurtosis is used when data is less varied (the distribution peak is higher at the mean and the spread is narrow)? a. Mesokurtic b. Platykurtic c. Leptokurtic

c. Leptokurtic

Which kurtosis is used when data has a large SD? a. Mesokurtic b. Platykurtic c. Leptokurtic

b. Platykurtic

Which kurtosis is used when data has a small SD? a. Mesokurtic b. Platykurtic c. Leptokurtic

c. Leptokurtic

Which kurtosis value is -ve a. Mesokurtic b. Platykurtic c. Leptokurtic

b. Platykurtic

Which kurtosis value is +ve a. Mesokurtic b. Platykurtic c. Leptokurtic

c. Leptokurtic

What does data with no skew look like?

The tail of a distribution curve is bell shaped

What does data with positive skew look like?

The tail of a distribution curve is longer on the right side (towards positive values on the x axis)

What does data with negative skew look like?

The tail of a distribution curve is longer on the left side (towards negative values on the x axis)

What is bimodal data?

Data with 2 modes

What is uniform data?

Looks like categorical data lined up instead of a curve

True or False? Bimodal and uniform data are normally distributed

False They are not normally distributed

We use sample statistics to infer ...?

Population parameters

True or False? We use population parameters to infer sample statistics

False We use sample statistics to infer population parameters

What is Sampling Error?

The degree to which sample statistics differ from underlying population parameters

The degree to which sample statistics differ from underlying population parameters This is known as...?

Sampling error

What are the 2 ways we can minimise error?

Sample size must be: 1. Representative (randomly selected) 2. Sufficient in size

Scores from a normally distributed population can be converted to z -scores What is the z-score formula?

z = (x - pop. mean) / sample mean

Percentage of scores within single standard deviation boundaries This is known as...?

Standard Normal Distribution

What is Standard Normal Distribution?

Percentage of scores within single standard deviation boundaries

What is sampling distribution?

Distribution of a statistic across an infinite number of samples (e.g. sampling distribution of the mean)

Distribution of a statistic across an infinite number of samples (e.g. sampling distribution of the mean) This is known as...?

Sampling distribution

Plotting all possible sample means gives us the ...?

Sampling distribution of the mean

Plotting all possible sample means gives us the sampling distribution of the mean Its mean is equivalent to the ...?

Population mean

Plotting all possible sample means gives us the sampling distribution of the mean Its standard deviation is given a special name ...?

The standard error

The standard deviation of the sampling distribution is known as..?

The standard error

What is the standard error?

The standard deviation of the sampling distribution

As sample size increases, the standard error ...?

Decreases

The standard error decreases as sample size increases What does this suggest?

Sampling error decreases as sample size increases

An estimate of the standard error, based on our sample This is known as...?

Estimated standard error

What is ESE?

An estimate of the standard error, based on our sample

What is the formula for ESE?

ESE = SD / sqrt sample size

What are the 3 characteristics of sampling distribution of the mean?

1. Mean equivalent to the population mean 2. Standard deviation is the ‘standard error’ 3. Always normally distributed

True or False? 5% of all sampled means will fall within ±1.96 standard errors of the population mean

False 95% of all sampled means will fall within ±1.96 standard errors of the population mean

What are CIs?

Interval estimates of population parameters

Interval estimates of population parameters This is known as...?

We use 95% CI in psychology What does this suggest?

We are declaring that there is still a chance that our estimates are wrong There’s a 5% chance that the population mean falls above/below the 95% CI limits

If there’s a 95% chance that the sample mean falls within the 95% bounds of the population mean, it follows that...?

There’s a 95% chance that the population mean falls within the 95% CIs of the sample mean

Is this H1 or H0? There is no difference between the population means

The probability of measuring a difference of that magnitude if the null hypothesis is true This is known as...?

p value

What is a p value?

The probability of measuring a difference of that magnitude if the null hypothesis is true

Threshold level of probability where we will be willing to reject the null hypothesis This is known as...?

alpha value

What is alpha value?

The threshold level of probability where we will be willing to reject the null hypothesis

If p < 0.5 ____ the hull hypothesis

Reject

What is type 1 error?

When H0 is true but you reject it

What is type 2 error?

When H0 is false but you fail to reject it

When H0 is true but you reject it Is this...? a. Type 2 error b. Type 1 error

b. Type 1 error

When H0 is false but you fail to reject it Is this...? a. Type 2 error b. Type 1 error

a. Type 2 error