Stats/Research Design Flashcards by Charlie Zapata

MANOVAs are for how many DVs

more than one

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One way ANOVAs are for how many IVs

one

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Factorial ANOVAs are for how many IVs

more than one

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Which is more powerful - ANOVA or MANOVA?

ANOVA

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It’s easier to find significant if separate ANOVAS are run for each IV but this increases the chance of _____

Type 1 error

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ANCOVA is used for removing the effects of a

Confound

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Selection bias is a threat to _____ and occurs when….

Internal validity….subjects are not randomly assigned to tx groups

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Quasi-experimental designs affect internal validity, external validity, both, or neither?

internal validity only

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Is external validity affected by non-random assignment?

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Experimental is classified as either ____ or ____

True or Quasi

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What is the primary feature that distinguishes a true experimental study from a quasi one? Is it considered the most powerful method of experimental control?

Random assignment…YES

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A source of systematic error that is irrelevant to a study’s hypotheses and confounds the results

extraneous variable

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Some technique to control for an extraneous variable include:

1) Random assignment to tx groups
2) Holding the EV constant
3) Matching subjects on the EV
4) Building the EV into the study (aka Blocking)
5) Statistical control of the EV

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What is the primary downfall of holding an EV constant to control for its effects?

Limited generalizability

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Matching subjects on the EV is most useful when?

The sample size is too small

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When Building the EV into the study (aka Blocking), the EV is then considered a?

Moderator variable

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In choosing a research design it is critical you choose one that minimizes the effects of ______ and _____ error.

systematic, random

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Internal validity is threatened when which 3 things happen?

1) Investigator can’t maximize the effects of the IV
2) Investigator can’t control the effects of any EVs
3) Investigator can’t minimize the effects of random error

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Name threats to internal validity

1) Maturation - changes within subjects over time
2) History - comes from out there
3) Testing
4) Instrumentation - tests themselves change in accuracy or sensitivity
5) Statistical Regression
6) Selection
7) Attrition
8) Interactions with Selection

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___ validity is always limited by its ____ validity

external limited by internal

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if you content there’s a causal relationship between variables in the context of the study, you _____ conclude that there’s a relationship for other people or circumstances

CANNOT

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A high degree of internal validity _____ guarantee external validity

DOES NOT

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the sd is the square root of the _____

variance

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variance squared is the _____

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A threat to internal and external validity is _____, which is when participants react to an IV in a certain way because they know they're being observed

reactivity

Three types of reactivity:

1) Evaluation Apprehension 2) Demand Characteristics 3) Experimenter Expectancy

When participants behave in a certain way to avoid negative evaluations

Evaluation apprehension

When the experimenter unintentionally provides subjects with cues about what's expected

Experimenter expectancy

Cues in the experimental setting that inform subjects of the purpse of the study

Demand characteristics

A threat to internal and external validity occurs when is pretest sensitization which can be controlled by ether of the following two

1) Solomon 4 group design (pretest is considered an IV) | 2) Don't administer a pretest

____ interference can be controlled by using a counterbalanced design, which means all subjects receive the treatment in ____ order

Multiple treatment, different

Multiple treatment interference can have _____ or ____ effects

order, carryover

A type of counterbalanced design

Latin square

Carryover and Order effects are common in _____ interference

Multiple treatment

When marginal means are different, one can _____ conclude that there are ____ effects

tentatively, main

A study can have _____ effects even if there is no ___ effect

interaction, main

There can be an combination of interaction and main effects. T or F

A set of data that uses ordinal, interval, or ratio scales can be organized using a frequency _______

polygon

Measures of central tendency

Mean, Median, Mode

If one score in a distribution is extremely high or low, the value of the ____ in not affected

median

of the 3 measures of central tendency, the ___ is least susceptible to sampling fluctuations

mean

the most susceptible to sampling fluctuations of the 3 measures of central tendency is the ____

mode

What are the best measures of central tendency for the following scales of measurement: 1) Nominal 2) Ordinal 3) Interval 4) Ratio

1) Nominal - Mode 2) Ordinal - Mode or Median 3) Interval - Mode, Median, Mean 4) Ratio - Mode, Median, Mean

These measures indicate the amount of heterogeneity or dispersion within a set of scores:

measures of variability

Name 3 measures of variability

1) Range 2) Variance 3) Standard Deviation

percentage of scores that fall between +/- 1 sd

68%

percentage of scores that fall between +/- 2 sd

95%

percentage of scores that fall between +/- 3 sd

99%

the # of cases that fall within limits that are defined by the sd - these limits are referred to as

areas under the normal curve

The central limit theorem states that the ____ mean is equal to the ____ mean and the sd of the sampling distribution is equal to the population sd divided by the ____ of the ____ size.

sample, population, square root of the sample size

The smaller the ____ size the ___ the standard error of the mean

smaller, larger

Formula for Variance

SS/N-1

To calculate the SS, you

subtract each score from the mean, then sq each, then add them all

S squared =

variance

Formula for SD

Square root of SS/N-1

The population mean is represented by a symbol that looks like __, while the sample mean looks like ___ or____

u | X or M

The population standard deviation is represented by a symbol that looks like __, while the sample standard deviation looks like ___ or ___

o | S or SD

The population variance is represented by a symbol that looks like __, while the sample variance looks like ___ or ___

o squared | S squared or V

Formula for the Standard Error of the Mean

o/sq rt of N

For there to be able to say there is an effect or the effects are probably due to IV variance and not due to error, you want your scores to fall within the ___ region and not the _____ region of a distribution

rejection, retention

If a score is in the rejection region, the null hypothesis is

rejected

The size of the rejection region is defined by

alpha

a Type __ error, which is ____ a true null, is defined by Alpha

I, rejecting

A Type __ error, which is ____ a false null, is defined by Beta

II, retaining

Power, which is correctly ____ a false null, is defined by

rejecting, 1 - Beta

Correctly retaining a ___ null is defined by ___

true, 1 - A

Nonparametric tests are for ____ and _____ data

nominal and ordinal

Parametric tests are for _____ and _____ data

interval and ratio

When selecting which inferential statistic, you want to first consider which 2 factors?

1) Scale of measurement of data to be analyzed | 2) Design of the study

the nonparametric version of the one-way ANOVA is the

kruskal-wallis

the nonparametric version of the t-test for independent samples is

mann-whitney U

the nonparametric version of the t-test for correlated samples is the

wilcoxon matched-pairs test

2 assumptions of parametric tests are that the value of interest is _______ in the population. When the study includes more than 1 group there is _______.

normally distributed, homoscedasticity

the variances of the populations the different groups represent are equal is referred to as ______

homoscedasticity

A violation of the parametric test assumptions, especially _______, increases the chance of which error or errors?

homoscedasticity, Type I and II

Parametric tests are considered _____, which means that some deviation from a normal curve or homoscedasticity won't invalidate results

robust

Some ways to maximize robustness are to:

1) Equal number of subjects in each group 2) Set alpha at a lower level 3) Increase sample size

Because nonparametric tests don't rely on a normal distribution, they're referred to as _____ free tests

distribution free

______tests are used to evaluate the ___ of a distribution rather than its mean, variance, or other parameter

nonparametric, shape

F-ratio =

MSB/MSW | mean squares between/mean sqaures within

Effect size can be represented by

Cohen's d | Eta squared

A high correlation between 2 or more predictors is referred to as _________, and IS or IS NOT desirable..why?

multicollinearity, IS NOT - means it is difficult to tell which predictor leads to change