Chapter 1 Flashcards
Continuous Variables
Continuous variables have values that are real numbers.
Convenience Sample
A convenience sample is a sample that is conveniently available. It is the most common type of biased sample.
Descriptive Statistics
Descriptive statistics are used to describe the characteristics of a collection of scores, without the goal of inferring something about a population parameter.
Discrete Variables
Discrete variables have fixed values. Discrete quantitative variables have values that are integers or whole numbers.
Inferential Statistics
Inferential statistics is the act of inferring population parameters from sample statistics.
Interval Scales
Interval scales have EQUAL UNITS OF MEASUREMENT but no absolute zero point.
Measurement Error
Measurement error refers to the fact that each time something is measured a slightly different score will be obtained
Nominal Scale
The values of variables measured on a nominal scale are qualitative and discrete and have no natural ordering.
Operational Measure
An operational measure is a tool used to measure a psychological construct. Very often, operational measures are derived from questionnaires. Operational measures may also derive from the speed and accuracy with which psychological tasks are completed.
Ordinal Scale
The values of variables measured on an ordinal scale are qualitative and discrete and have a natural ordering, but they do not have a unit of measurement.
Parameter
A parameter is a numerical characteristic of a population.
Population
A population comprises the scores on a variable of interest, obtained from individuals that share some characteristic of interest.
Psychological Construct
A psychological construct is a hypothetical attribute (such as intelligence, introversion, or happiness) that is thought to explain some aspect of behavior, but which cannot be measured directly with a physical measuring device.
Qualitative Variables
Qualitative variables have values that are qualities or categories. They are also referred to as nominal or categorical variables.
Quantitative Variable
Quantitative (scale) variables have values that are numbers. They often reflect how much of some quantity an individual possesses.
Ratio Scales
Ratio scales have units of measurement and an absolute zero. The ratio of two values on a ratio scale expresses their RELATIVE DISTANCES from 0.
Reliable
A reliable measuring device gives very similar (if not identical) measurements each time it is applied to the same object.
Sample
A sample is a subset of a population.
Sampling Bias
Sampling bias means that not all members of the population had an equal chance of being selected in the sample. Sampling bias can and should be avoided.
Sampling Distribution
A sampling distribution is a probability distribution of all possible values of a sample statistic based on samples of the same size.
Sampling Error
Sampling error is the difference between a statistic and the parameter it estimates. Sampling error cannot be avoided; it is an inevitable feature of random sampling.
Score
A score is the value that an individual has on a particular variable.
Simple Random Sampling
Simple random sampling means that all members of the population had an equal chance of being selected in the sample.
Statistic
A statistic is a numerical characteristic of a sample.
Valid
A measuring device is valid if it measures what it is supposed to measure.
Variables
Variables are physical or abstract attributes or quantities that we wish to measure. A variable can take on specific values.
