CH 2 Stats
A frequency distribution lists the _________ of occurrences of each category of data, while a relative frequency distribution lists the _________ of occurrences of each category of data.
number, proportion
Pareto Chart
a bar graph whose bars are drawn in decreasing order of frequency or relative frequency
What is an ogive?
A graph that represents the cumulative frequency or cumulative relative frequency for the class
class width
The _________________ is the difference between consecutive lower class limits.
classes
are the categories by which data are grouped
The cumulative relative frequency for the last class must always be 1. Why?
All the observations are less than or equal to the last class.
skewed right
For annual household incomes in a country state whether you would expect a histogram of the data to be bell-shaped, uniform, skewed left, or skewed right. Choose the correct answer below.
bell-shaped
For scores on a standardized exam such as the SAT, state whether you would expect a histogram of the data to be bell-shaped, uniform, skewed left, or skewed right.
In a relative frequency distribution, what should the relative frequencies add up to?
The relative frequencies add up to 1
The statement is true. Any correctly constructed frequency distribution is valid. However, some choices for the categories or classes give more information about the shape of the distribution.
There is not one particular frequency distribution that is correct, but there are frequency distributions that are less desirable than others.
lower, upper
The ______ class limit is the smallest value within the class and the ______ class limit is the largest value within the class.
quantitative Time-series plots are used to identify trends in the data over time.
What type of variable is required when drawing a time-series plot? Why do we draw time-series plots?
Classes shouldn't overlap so there is no confusion as to which class an observation belongs.
Why shouldn't classes overlap when summarizing continuous data in a frequency or relative frequency distribution?