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?