Chapter 1 Flashcards
Individuals
The objects described by a set of data. Individuals may be people, animals, or things.
Variable
Any characteristic of an individual. A variable can take different values for different individuals.
Categorical Variable
Places individual into one of several groups or categories.
Quantitative Variable
Takes numerical values for which it makes sense to find an average.
Discrete Variable
When a variable cannot take on any value between its min. and max. value (Flipping a coin: Cannot get 1/2 tails or 2.5 heads)
Continuous Variable
When a variable can take on any value between its minimum value in its maximum value.
Univariate Data
when you only look at one variable.
Bivariate Data
when you conduct a study that examines the relationship between two variables.
Population
The total set of observations that can be made. (if you were studying the weight of adult women, the population is the set of weights of all the women in the world)
Sample
A set of observations drawn from a population.
Census
A study that obtains data from every member of the population. Most of the time a census is not practical, because of the cost and/or time required
Distribution
The distribution of a variable tells you that hat values the variable takes and how often it takes these values.
Inference
The process of using data analysis to deduce properties of an underlying distribution of probability.
Frequency Table
When a table shows frequency for a categorical variable.
Relative Frequency
Frequency count for subgroup of a population divided by the total count. (Percent)
Table
An arrangement of data in rows and columns.
Roundoff Error
When rounded percents do not add to 100% and are only the effect of rounding off results. EX: 99.9%
Pie Chart
Show the distribution of a categorical variable. Need all categories that make up the whole or an “Other” category.
Bar Graph
Represent each category as a bar. Bar heights show the category counts or percents. Can compare any set of quantities. Important that width of bars is equal when making them
Two-Way Table
Organizes data about two categorical variables measured for the same set of individuals. Groups outcomes into categories.