Section 2.1: Frequency Distributions for Organizing and Summarizing Data

How to calculate relative frequency?

Divide each frequency number by the sum. Convert the resulting decimal to a percentage

Range

Highest value-lowest value

A class boundary is always

a number ending in .5

Relative frequency

Class frequency/sum of all frequencies

The sum of the relative frequencies in a relative frequency distribution must be

close to 1 (100%)

cumulative frequency

frequency for each class is the sum of the frequencies for that class and all previous classes

normal distribution

Numbers make a bell curve

A histogram is only for what type of data

Quantitative

Frequency polygon

Connecting the dots of the midpoints atop the bars or on the line if the data point has no bar above it

what does a dotted line mean

the data point is not included in the set

what does a solid line mean

the data point is included in the set

class width

difference between each number in the class. Ex. upper class 1 is 5 and upper class 2 is 10, the class width is 5 because 5+5=10

class midpoints formula

upper class + lower class / 2