Chapter 1: Introduction to Statistics Flashcards
What is statistics?
Statistics is a branch of mathematics used to summarize, analyze, and interpret a group of numbers or observations.
What is a population?
A population is the set of all individuals, items, or data of interest. This is the group about which scientists will generalize.
What are the two branchs of statistics?
Descriptive and inferential
What is descriptive statistics?
Descriptive statistics are procedures used to summarize, organize, and make sense of a set of scores called data and are typically presented graphically, in tabular form (in tables), or as summary statistics (single values).
What is inferential statistics?
Inferential statistics are procedures used that allow researchers to infer or generalize observations made with samples to the larger population from which they were selected.
What is a sample?
A sample is a set of individuals, items, or data selected from a population of interest.
What is an operational definition?
An operational definition is a description of some observable event in terms of the specific process or manner by which it was observed or measured.
What are the three requirements for the experimental method?
Manipulation, randomization, comparison/control
What is the quasi-experimental method?
A quasi-experiment is a study that (1) includes a quasi-independent variable and/or (2) lacks a comparison/control group.
What is the correlational method?
The correlational method can determine whether a relationship exists between variables, but it lacks the controls needed to demonstrate cause and effect.
What are scales of measurement?
Scales of measurement identify how the properties of numbers can change with different uses.
What are the four scales of measurement?
Nominal, ordinal, interval, ratio
What are nominal scales?
Nominal scales are measurements in which a number is assigned to represent something or someone.
Common examples of nominal numbers include ZIP codes, license plate numbers, credit card numbers, country codes, telephone numbers, and Social Security numbers.
What are ordinal scales?
Ordinal scales are measurements that convey order or rank alone.
Examples of ordinal scales include finishing order in a competition, education level, and rankings.
What are interval scales?
Interval scales are measurements that have no true zero and are distributed in equal units.
Examples include a rating scale and temperature.
What are ratio scales?
A ratio scale is equidistant, has a true zero, and is the most informative scale of measurement.
Common examples of ratio scales include counts and measures of length, height, weight, and time.
What is an independent variable?
An independent variable (IV) is the variable that is manipulated in an experiment.
What is a dependent variable?
The dependent variable (DV) is the variable that is measured in each group of a study, and is believed to change in the presence of the independent variable.
It is the “presumed effect.”
What is the quasi-experimental method?
A quasi-experiment is a study that (1) includes a quasi-independent variable and/or (2) lacks a comparison/control group.
In a typical quasi-experiment, the variables being studied cannot be manipulated, which makes random assignment impossible.
What is a continuous variable?
A continuous variable is measured along a continuum at any place beyond the decimal point. A continuous variable can thus be measured in fractional units.
Time (in seconds), then, is a continuous variable.
What is a discrete variable?
A discrete variable is measured in whole units or categories that are not distributed along a continuum.
For example, the number of brothers and sisters you have makes sense only when given in whole units or numbers
What is a quantitative variable?
A quantitative variable varies by amount. This variable is measured numerically and is often collected by measuring or counting.
What is a qualitative variable?
A qualitative variable varies by class. This variable is often represented as a label and describes nonnumeric aspects of phenomena.
