Exam 1 Definitions

Chapters 1 and 2

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Sum of the lower and upper limits of the class divided by two

Midpoint formula

(lower class limit + Upper class limit)/2

What is relative frequency?

Relative frequency of a class is the portion, or percentage, of the data that falls in that class

Formula for relative frequency

Class frequency(f)/sample size(n)

Cumulative frequency definition

The sum of the frequencies of that class and all previous classes

What is the cumulative frequency of the last class equal to?

The sample size, n(n= sum of all values)

What is a frequency histogram?

It is a graph of the frequency distribution that is used to represent the frequency distribution of a data set

What are class boundaries?

The numbers that separate classes without forming gaps between them

What is a frequency polygon?

A line graph that emphasize the continuous change in frequencies

What is a relative frequency histogram?

Has the same shape and the same horizontal scale as the corresponding frequency histogram

the vertical scale measures the relative frequencies, not the frequencies

What is another name for a cumulative frequency graph

Ogive

What is an ogive?

A line graph the displays the cumulative frequency of each class at its upper class boundary

What is a cumulative frequency graph used for?

To describe the number of data entries taht are less than or equal to a certain value

What is the measure of central tendency?

A value that represents a typical, or central, entry of a data set

A value that represents a typical, or central, entry of a data set

Mean, median, and mode

What is the mean of a data set?

The sum of the data entries divided by the number of entries

What is the median?

The value that lies in the middle of the data when the data set is ordered

Measures the center of an ordered data set by dividing it into two equal parts

How to find the median?

Odd number of entries: median is the middle data entry

Even number of entries: median is the mean of the two middle data entries

What is the mode?

The data entry that occurs with the greatest frequency

Can a data set have no mode/ more than one mode?

Yes, if no entry is repeated than there is no mode, and if two entries occur with the same greatest frequency each entry is a mode

Definition of bimodal

When two entries occur with the same greatest frequency

What is an advantage of using the mean? What is a disadvantage of using the mean?

The mean takes into account every entry of a data set, but it is greatly affected by outliers