Final Definitions Flashcards
data
facts and figures collected, analyzed, and summarized for presentation and interpretation
data set
all data collected in a particular study
elements
entities on which data are collected
variable
characteristic of interest for the elements
observation
set of measurements obtained for a particular element
categorical data
data that can be grouped by specific categories
quantitative data
data that use numerical values to indicate how much or how many are referred to
categorical variable
variable with categorical data
quantitative variable
variable with quantitative data
population
set of all elements of interest in a particular study
sample
subset of the population
frequency distribution
tabular summary of data showing the number (frequency) of observation in each of several non-overlapping categories or classes
relative frequency distrivution
shows the fraction or proportion of observations belonging in a class (ie 0.38)
relative frequency of a class=frequency of a class/n
percent frequency distribution
summarizes the percent frequency of data for each class ie (38%)
bar chart
graphical display for depicting categorical data summarized in a frequency, relative frequency, or percent frequency distribution
-categorical data: gap between bars
pie chart
presents relative frequency and percent frequency distributions for categorical data
dot plot
show the details of the data and are useful for comparing the distribution of the data for 2 or more variables
histogram
bar chart with no gaps
stem and leaf display
used to show simultaneously the rank order and shape of a distribution of data
variance
measure of variability that utilizes all the data
based on the difference between the value of each observation, xi, and the mean
standard deviation
positive square root of the variance
coefficient of variation
indicates how large the standard deviation is relative to the mean
tree diagram
helps visualize a multi step random expirement
discrete random variable
a random variable that may assume either a finite number of values or an infinite sequence of values ie 0,1,2,3,4 etc