W2: RQ for Associations (Page 1-22) Flashcards by andy Sitoh

What does a good research question contain:

) A question
) All constructs being investigated
) The study population
) A verb that indicates the type of relationship among constructs being proposed

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What are the 3 types of verbal forms of relationships

Difference; Association; Prediction

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What does DAP involve

Association = Correlation
Prediction = Linear Regression
Difference = Differences between groups

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What is a population

COMPLETE set of all individuals relevant to our research question

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What is a sample

SUBSET of individuals selected by some sampling scheme from the population, assumed to be representative of that population

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How many population and samples are relevant in our research question

1 population but there can be (theoretically) many possible samples drawn from that population

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What is a construct

Unobservable attributes to explain human behavior

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What is a measure. What are some conditions for a measure?

Method to measure people on a construct to obtain a construct score.

Measure must be valid and reliability

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What is a score

Numerical value of the construct measure

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What is a raw score and what are they generally indicated by

Values obtained directly from the construct measure.

They are generally indicated by a capital letter (X,Y), which is a variable containing a set of values

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What is a deviation score and what are they generally indicated by.

Hence

The mean is subtracted from the individual score.

They are generally indicated by lower case letter (x,y)

Hence, X - mean(x) = x

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What is a z score. What is the mean and sd of z scores

Particular kind of standardized score by dividing a deviation score by standard deviation

Mean = 0
SD = 1
(always)

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What is a standardized score (Generally speaking)

Raw scores that have been transformed such that they have a predefined mean and a predefined scaling for each unit standard deviation.

IQ: 100
Z: 15

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Why do we call something a random variable

Each value has an associated probability of ocurrene

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What is the difference between continuous and discrete random variables

Continuous: Any numerical value within a defined interval (e.g. 0 to 100)

Discrete: Finite number of distinct values (e.g. integers 1,2,3,4,5)

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If both measures are continuous, we use ___

Correlation

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If both measures are categorical, we use ____

Contingency Tables

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What is summary characteristics

Some kind of aggregation undertaken on
the individual values in one or more variables to produce a single quantity that is
informative about the values (e.g. mean; standardd deviation)

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PPSS

Population - Parameter; Sample - Statistics

What is population parameter and sample statistics

PP = Aggregated summary characteristic of individual scores derived from all members of a population

SS = Aggregated summary characteristic of individual scores calculated in a single sample drawn from a population (i.e. there can be many values for a sample statistic, one for each sample drawn from the same population)

Do sample distributions vary. What does this imply about the sample mean.

Yes. Sample mean, etc… will randomly differ

What is the benefit of scatter plot

Useful for indicating an association. Can be linear/non-linear

What is a Pearson Correlation

Measure of LINEAR SYMMETRIC association between 2 CONTINUOUS variables

How are associations between multiple variables often presented

Often a correlation matrix

What do we use to identify patterns among multiple variables

Correlation plots are preferable for identifying patterns among multiple variables

Is positive or negative in value important when discussing association strength

No. We ignore positive or negative

What is the population correlation coefficient

p (rho). Correlation calculated on everybody in a population

What is the sample correlation coefficient

r. estimated on a sample drawn from a population

Do we often know p (rho)?

Almost certainly unknown. We use the known sample value to estimate the unknown population value (point of research)

What is a sampling distribution/distribution of values

A sample statistic obtained from a large number of repeated samples taken from a population

What are the effects of having a larger sample size

Larger sample reduces variability of the sampling distribution (i.e. more narrow)

What is the SD of the sampling distribution

Standard Error.

What can each sample statistic value be regarded as

An estimate of the population parameter value

What is a confidence interval. What does it have.

* Range of plausible values* of an unknown population parameter based on the (1) value of a single sample statistic and (2) its standard error. - Lower bound and upper bound value. Typically set as 95%.

What is a random sample. How is it typically done

A Simple Random Sample is one where each member of the population has an EQUAL probability of being selected. It is typically done via. a uniform probability distribution (without replacement)

When we transform a score into a standardized score, what actually changes

Only the scaling of the variable

When we transform item scores as continuous, what we declare them in R

Declare them as numeric variables

When we treat item scores as discrete, what we delcare them in R

Declare them as factor variable

If we measure everyone in the population on a construct, then the set of scores form a ...

Population distribution (There is only one)

If we measure everyone in a single sample from a construct, then the set of scores form a ...

Sample Distribution (There are many possible)

Will the population distribution be larger/smaller than a sample distribution

Much Larger

What does it mean by "symmetry" in a Pearson Correlation

Correlation of X and Y = Correlation of Y and X

What is the correlation value always between

-1 to +1

Will any kind of sample statistic have a corresponding sampling distribution. Elaborate

In Theory, yes. - Anytime we have a distribution of values, we can calculate summary characteristics. Under conditions, as Sampling increases, 1. ) Mean of sampling distribution will get closer to unknown population parameter value 2. ) SD can be calculated (known as Standard Error)

How many types of scores are there

1. ) Raw Score 2. ) Deviation Score 3. ) Z-Score 4. ) Standardised Score Deviation, Z and Standardized Scores are transformations of Raw Score

What do the scores and the transformation actually change

Only the scaling of the variable are changed