Flashcards in Chap 1 Data Deck (29):

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## Chi-squared distributions:

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

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## Constant

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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.

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## Convenience Sampling

### Selecting a sample based on ease of access or availability

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## 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

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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.

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## Descriptive Statistics

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

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## Dichotomous Variable

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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.

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## Frequency

### How often a score occurs in a distribution

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## 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.

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## Inferential Statistics

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

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## Interval or Ratio Variable

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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.

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## Mean

### The arithmetic average of a distribution of scores

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## 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

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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

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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.

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## 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.

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## 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.

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## Representative Sampling

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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

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## 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.

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