Stats 2: Frequency Distribution and Graphs

What is the formula to find the percentage of each class in a pie chart?

percentage = f/n x 100

bar graphs are used to represent what kind of data?

qualitative or categorical

pareto charts are used to represent what type of data?

qualitative or categorical

define time series graph

represents data that occur over a specific period of time

define bar graph

represents the data by using vertical or horizontal bars whose heights or lengths represent the frequencies of the data

what are the 3 steps of constructing a grouped frequency distribution?

step 1, determine the classes. step 2, tally the data, step 3, find the numerical frequencies from the tallies, and find the cumulative frequencies.

If there is no remainder after finding the width what do you do?

you will need to add an extra class to accommodate all the data.

what are the 3 basic steps to create a pareto chart?

1. arrange data from large to small, 2. make bars equal in width, 3. make frequency unity equal in size.

what are the 3 basic steps to creating a stem and leaf plot?

1. arrange data in order, 2. separate data according to first digit, 3. graph.

What are the 4 basic steps in creating a time series graph?

1. draw and label y and x axis, 2. label x axis with years and y axis with freq, 3. plot pts, 4. draw line connecting pts.

what are the 7 steps of determining classes in grouped frequency distribution?

1. find the highest and lowest values, 2. find the range 3. select the number of classes desired 4. find the width by dividing the range by the number of classes and rounding up 5. select a starting point (usually the lowest number) 6. find the upper class limits 7. find the boundaries.

what are the 6 basic rules to construct a frequency distribution?

1. there should be between 5-20 classes, 2. preferable to have a class width with an odd number, 3. classes must be mutually exclusive, 4. the classes must be continuous, 5. classes must be exhaustive, 6. classes must be equal in width.

Sum of relative frequency will always equal to what?

1.0

how do you find the lower boundary?

Lower limit - 0.5 = lower boundary / example: 27.5 - 0.05 = 27.45, another example is 45 - 0.5 = 44.5

define pie chart

a circle that is divided into sections or wedges according to the percentages of frequencies in each category of the distribution.

define cumulative frequency distribution

a distribution that shows the number of data values less than or equal to a specific value (usually an upper boundary).

what is a histogram

a graph that displays the data by using contiguous vertical bars of various heights to represent the frequencies of the class.

define frequency polygon

a graph that displays the data by using lines that connect points plotted for the frequencies at the midpoints of the classes. frequencies are the heights of the points.

define dot plot

a statistical graph in which each data value is plotted as a point (dot) above the horizontal axis.

how do you find the upper boundary?

add .5 to the upper limit / example: 35 +.5 = 35.5 , another example 123.45 + .005 = 123.455

Name 5 other types of graphs

bar graph,, pareto chart, time series chart, pie graph, and dot plot.

what is a compound bar graph?

bar graphs used to compare date for 2 or more groups

What are the 3 types of frequency distribution?

categorical frequency distribution, grouped frequency distribution, and ungrouped frequency distribution.

what are 4 basic columns for categorical frequency distribution table?

class/tally/frequency/percent

define raw data

data collected in original form

define stem and leaf plot

data plot that uses part of a data value as the stem and part of the data value as the leaf to form groups or classes.

define categorical frequency distribution

data that can be placed in specific categories, such as nominal or ordinal level data, such as political affiliations.

What is the formula to find the degree of each class in a pie chart?

degree = f/n x 360

How do you find the width with just the data set?

find the width by dividing the range by the number of classes and rounding up.

in a horizontal bar graph, the frequencies go on which axis?

frequencies go on the x axis

in a vertical bar graph, frequencies go on which axis?

frequencies go on the y axis

define cumulative frequency

graph that represents the cumulative frequencies for the classes in a frequency distribution.

define ogive

graph that represents the cumulative frequencies for the classes in a frequency distribution.

what are the 3 most commonly used graphs in statistics?

histogram, frequency polygon, and ogive (cumulative frequency graph).

define class limits

lower and upper class limits represent one class

what are categorical frequency distributions?

nominal or ordinal level data that can be placed in categories

in a time series graph, the years are represented on which axis? frequencies?

years are on the x axis, and freq. is on the y axis.

what is the class width and how do you find it

the amount that separates each class. it is found by subtracting the upper or lower class limit of one class from another. also found by subtracting boundaries of a single class.

what is the class midpoint Xm and how do you find it

the midpoint between a class, found by adding upper and lower boundary and dividing by 2.

define frequency

the number of data values contained in a specific class.

define frequency distribution

the organization of raw data in table form, using classes and frequencies.

define class

the quantitative or qualitative category

what are class boundaries?

these numbers are used to separate the classes so that there are no gaps in the frequency distribution.

How do you find the relative frequency

to convert a frequency into a proportion or relative frequency, divide the frequency for each class by the total of the frequencies.

cumulative frequency graphs are used for what?

to visually represent how many values are below a certain upper class boundary.

define pareto chart

used to represent a frequency distribution for a categorical variable, and frequencies are displayed by the heights of vertical bars, arranged from HIGHEST to LOWEST.

define grouped frequency distributions

used when the range of the data is large.

how do you find the cumulative frequency?

values are found by adding the frequencies of the classes less than or equal to the upper class boundary of a specific class.

define relative frequency graphs

when frequencies are converted into proportions instead of raw data. the sum of the frequencies will be 1.0

define open-ended distribution

when the first or last class has no specific limit.

when do you use ungrouped frequency distribution

when the range of the data values is relatively small.

in ogive, what represents the y axis, x axis?

y axis is the cumulative frequency, x axis are class boundaries.

in a histogram, what represents the y axis, the x axis?

y axis is the frequency while the x axis are the class boundaries

in a frequency polygon, what represents the y axis, the x axis?

y axis is the frequency, and the x axis are midpoints of the class boundaries.

when finding the width, if there is a remainder, what do you do?

you round UP when there is a remainder