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Flashcards in Chap 1 Data Deck (29):
1

Chi-squared distributions:

A family of distributions associated with the chi-squared statistic (X2)

2

Constant

A construct that has only one value.
e.g. if every member of a sample was 10 years old, the "age" construct would be constant.

3

Convenience Sampling

Selecting a sample based on ease of access or availability

4

Correlational research design

A style of research used to examine the associations among variables. Variables are not manipulated by the researcher in this type of research design.

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Dependent Variable

The values of the dependent variable are hypothesized to depend on the values of the independent variable.
e.g. height depends in part on gender.

6

Descriptive Statistics

Statistics used to describe the characteristics of a distribution of scores.

7

Dichotomous Variable

A value that has only two discrete values.
e.g. a pregnancy variable can have a value of 0 for " not pregnant" and 1 for "pregnant"

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Distribution

Any collection of scores on a variable

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Experimental research design

A type of research in which the experimenter, or researcher, manipulates certain aspects of the research. These usually include manipulations of the independent variable and assignment of cases to groups.

10

Frequency

How often a score occurs in a distribution

11

Generalize (or Generalizability)

The ability to use the results of the data collected from a sample to reach conclusions about the characteristics of the population, or any other cases not included in the sample.

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Independent Variable

A variable on which the values of the dependent variable are hypothesized to depend. Independent variables are often, but not always, manipulated by the researcher.

13

Inferential Statistics

Stats derived from a sample data, that are used to make inferences about the population from which the sample was drawn.

14

Interval or Ratio Variable

Variables measured with numerical values with equal distance, or space b/w each number.
e.g. 2 is twice as much as 1, 4 is twice as much as 2, the distance b/w 1 and 2 is the same as the distance b/w 2 and 3.

15

Mean

The arithmetic average of a distribution of scores

16

Nominally scaled variable

A variable in which the numerical values assigned to each category are simply labels rather than meaning numbers.

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Normal Distribution

A bell-shaped frequency distribution of scores that has a mean, median, and mode in the middle of the distribution and is symmetrical and asymptotic.

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Ordinal Variable

Variables measured with numerical values where the numbers are meaningful (e.g. 2 is larger than 1) but the distance b/w the numbers is not constant.

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Parameter

A value, or values derived from a population data

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Population

The collection of cases that comprise the entire set of cases with the specified characteristics.
e.g. all living adult males in the United States.

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Qualitative (or categorical) Variable

A variable that has discrete categories. if the categories are given numerical values, the values have meaning a nominal reference but not as numerical values.
e.g. in 1 = "male" and 2="female", 1 is not more or less than 2

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Quantitative ( or continous) Variable

A variable that has assigned values and the values are ordered and meaningful, such that 1 is less than 2, 2 is less than 3, and so on.

23

Random assignment

Assignment members of a sample to different groups
(e.g. experimental and control) randomly, of without consideration of any of the characteristics of sample members.

24

Random Sample ( or random sampling)

Selecting cases from a population in a manner that ensures each member of a population has a equal chance of being selected into the sample.

25

Representative Sampling

A method in selecting a sample in which members are purposely selected to create a sample that represents the population on some characteristic(s) of interest.
eg. when a sample is selected to have the same percentages of various ethnic groups as the larger population).

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Sample

A collection of cases from a larger population

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Statistic

A characteristic, or value derived from a sample data

28

t distribtuions

A family of distributions associated with the t statistic, commonly used in the comparison of sample means and tests of statistical significance for correlation coefficients and regression slopes.

29

Variable

Any construct with more than one value that is examined in research.