# Research Methods Flashcards

Independent Variable

The variable whose effect is being studied

Dependent Variable

The variable expected to change due to variations in the independent variabble

What is the difference between a true experiment and a quasai experiment and correlational study.

True experiment: Independent var is manipulated, subject is randomly assigned to different groups

Quasi: no random assignment

Correlational study: no manipulation of independent var

What is another name for a naturalistic observation?

A field study

Population is

The total number of subjects that fit into a specific characteristics. i.e. people whom live in the US. People over 40 etc.

Sample

Is a sampling of people that is representative of the larger population.

The best way for researchers in getting an accurate sample?

A random sample.

What is another type of random sample?

Stratified random sample

What does a random stratified sample

It is a random sample that includes specific groups in proportion with the larger population. An attempt to get a more accurate measure.

Describe Between subject design

subject is exposed to only one level of independent variable. The subjects are assigned ranomly to groups and subjects are not given the same level of IV as another group.

Can groups differ on chance even with random selection?

Yes

What is matched subject design

Where the experimenter matches the two groups. So that people with similar abilities or characteristics are matched together and then studied together. For example if there is variability of intelligence between groups and intelligence is the dependent

What is within subjects design research

The subjects own performance is the basis of comparison. The crucial thing here is that the subject is exposed to more than one condition, allowing the researcher to separte the effects of individual differences in intelligence from the effects of the IV. A-B, A-B-A etc

What are the most obvious problems in research design

Experimenter bias

Demand Characteristics

Placebo Effect

Hawthorne Effect

Describe the placebo effect:

When people show positive effects to sham treatment, intert substances, or no active treatment.

What is the Hawthorne effect

The effect that being observed has on behavior

Describe demand characteristics

Cues in research situations that suggest to the subject what is expected.

Describe experimenter bias

How the experimenter biases the study in all aspects, methods, statistics, design and reporting.

What are the two major categories of statistics?

Descriptive and inferential

What is descriptive statistics concerned with?

Is concerned with organizing, describing, quantifying, and summarizing a collection of actual observations.

What is inferential statistics concerned with?

Inferential statistics researchers generalize beyond actual observations.

Frequency distributions

A chart that is used as a graphic representation of the frequency of one variable of the data.

Measures of central tendency are

mean, median and mode

mode

Is the most frequent value

If there are two modes, what is it called?

Bimodal

A distribution can have 3 or 4 modes

then it is polymodal

Median is the central number

Count the numbers and figure out which one is exactly in the middle. If even average the two middle numbers.

Mean

Is the average of the data across all subjects. Or in otherwords the numerical 50%

What are numbers that don’t fit the central tendency?

outliers

What is the most sensitive measure to extreme outliers?

mean

What are measures of variability

Range

Standard deviation

variance

Variability or dispersion scores

Range

Is the smallest number subtracted from the largest

Standard deviation

The average scatter away from the mean. (square root of the variance)

Variance

The square root of the STD

What is a normal distribution

It is a bell shaped curve of the data that follows a typical pattern.

With normal distribution how can you tell the percentile of the score the person is in?

By using the z-score

What is the z-score?

The number of STD away from the mean.

What is 1 z score account for

34% on one side of the distribution, 68% on both sides

What does 2 z score account for

14% or 13.6% between 1 and 2, aprox 48.5% on one side of the distriubution and aprox 97% on both sides

What is above 2 zscore

1.5% on one side or 3 % on both sides

What is a T-score?

It is a standardize score with a STD of 10. Often used for test scoring because of the nice even round numbers.

What is a non-normal distribution?

When the data does not fit a normal distribution

If the mean is less than the median then

the data is skewed to the left (lower numbers)