WHAT IT IS Frequency distributions summarize and compress data by grouping it into classes and recording how many data points fall into each class. That is, they show how many observations on a given variable have a particular attribute. For example, a survey is taken of 50 people's favorite color. The frequency distribution might indicate 15 people selected green, 12 blue, 6 red, 7 yellow, and 10 purple. Converting these raw numbers into percentages would then provide an even more useful description of the data. The frequency distribution is the foundation of descriptive statistics. It is a prerequisite for both the various graphs used to display data and the basic statistics used to describe a data set  mean, median, mode, variance, standard deviation, and so forth. Note that frequency distributions are generally used to describe both nominal and interval data, though they can describe ordinal data.
WHEN TO USE IT A frequency distribution should be constructed for virtually all data sets. They are especially useful whenever a broad, easily understood description of data concentration and spread is needed. Most data provided by third parties are grouped into a frequency distribution.
Preparation The steps in preparing frequency distributions manually are as follows: C Collect raw data from entity records, interviews, surveys, etc. C If data are nominal, list the classes into which a data point might fall. If data are interval, select an appropriate number of data classes. C Calculate the absolute frequency of each class, i.e. the raw number of data points in each class. Note that the sum of all absolute frequencies must equal the sample size. C Calculate the relative frequency by dividing the absolute frequency by the sample size. This reveals the proportion or percent of data points in each class. Note that the sum of all relative frequencies must be 1. C Calculate the cumulative frequency for each class by adding the number or...
...I found the concept on frequencydistribution using Google and the search words “frequencydistribution” at http://www.mathsisfun.com/data/frequencydistribution.html
This website is geared towards younger people and therefore breaks down frequencydistribution into very basic terms: values and their frequency (how often each value occurs). The website uses the example of a child’s soccer team and how many goals they scored in recent games.
For the assignment this week, I have chosen to use the raw data of shoe sizes of my coworkers and how often these shoe sizes occur and show how to put them into a frequencydistribution table. Because there are only 4 females in my division, I have stuck with only the male shoe sizes of 20 coworkers.
Raw Data
10 12 9 10 11
8 10 11 10 9
9 8 11 10 10
12 10 9 10 11
Each raw data value is now placed into a class. Since my range of data is small, I’m going to use single data values.
Distribution Table
Class Limits Tally Frequency
8 II 2
9 IIII 4
10 IIII IIII 8
11 IIII 4
12 II 2
Total: 20
This can also be done in excel by following the instructions for a categorical frequency table for qualitative or discrete data on page 215 (49) of our textbook.
Taking it a step forward, the information can then be used in a pie chart to visually...
...the iRiver, and the Magic Star MP3. To summarize the consumer responses with a frequency table, how many classes would the frequency table have?
4. Two thousand frequent Midwestern business travelers are asked which Midwest city they prefer: Indianapolis, Saint Louis, Chicago, or Milwaukee. The results were 100 liked Indianapolis best, 450 liked Saint Louis, 1,300 liked Chicago, and the remainder preferred Milwaukee . Develop a frequency table and a relative frequency table to summarize this information.
5. Wellstone, Inc., produces and markets replacement covers for cell phones in a variety of colors. The company would like to allocate its production plans to five different colors: bright white, metallic black, magnetic lime tangerine orange, and fusion red. The company set up a kiosk in the Mall of America for several hours and ask randomly selected people which cover color was their favorite:
Bright white 130
Metallic black 104
Tangerine orange 455
Fusion red 286
A. What is the table called?
B. Draw a bar chart in the table.
C. Draw a pie chart.
D. If Wellstone, Inc., plan to produce million cell phone covers, how many of each color should it produce?
11. Wachesaw Manufacturing, Inc., produced the following number of units in the last 16 days.
27, 27, 27, 28, 27, 25, 25, 28
26, 28, 26, 28, 31, 30, 26, 26
the information is to be organized into a frequency...
...SPSS: Grouped FrequencyDistribution
FIRST STEP: Under the Transform menu, choose Visual Binning… This
command assists you in creating a new variable that groups the data. You
will then use the new variable to create a grouped frequencydistribution.
• From the Variables list box, click on wt (weight) and then on the arrow to
move it to the Variable to Band list box. Click Continue.
• Select wt in the left box. Near the top of this dialog box, enter a name for
your new variable (such as wt_groups) in the “Binned Variable” box
(cannot have any spaces in the name).
• Near the lower right, click Make Cutpoints…
• We are going to make Equal Width Intervals, which is the default selection
in this dialog box. You have to fill in 2 of the 3 fields; for our purposes, fill
in “Number of Cutpoints” and “Width”.
• As discussed above, generally 10 to 15 intervals works well. The Number
of Cutpoints = [number of intervals – 1]. (Why? * ) Thus, if we want 10
intervals, we’ll enter 9 in the “Number of Cutpoints” box.
• For the “Width” of each interval: (a) find the difference between the lowest
and highest score in your data (you can see these values in the
background dialog box behind the active dialog box); (b) divide the
difference by the number of intervals (in this example, [122.7 – 65] / 10 =
5.77); and (c) round up to the whole number (6.0). Enter that number as
the interval Width.
*...
...FREQUENCY POLYGONS
W H AT I S A F R E Q U E N C Y P O LY G O N
Frequency polygons are a graphical device for
understanding the shapes of distributions. They
serve the same purpose as histograms, but are
especially helpful for comparing sets of data.
Frequency polygons are also a good choice for
displaying cumulative frequencydistributions.
H O W T O C R E AT E A F R E Q U E N C Y
P O LY G O N
To create a frequency polygon, start just as for histograms, by
choosing a class interval. Then draw an Xaxis representing the
values of the scores in your data. Mark the middle of each class
interval with a tick mark, and label it with the middle value represented
by the class. Draw the Yaxis to indicate the frequency of each class. Place
a point in the middle of each class interval at the height corresponding to
its frequency. Finally, connect the points. You should include one class
interval below the lowest value in your data and one above the highest
value. The graph will then touch the Xaxis on both sides.
E X A M P L E O F A F R E Q U E N C Y TA B L E
Lower
Limit
Upper
limit
Count
Cumulativ
e
29.5
39.5
0
0
39.5
49.5
3
3
49.5
59.5
10
13
59.5
69.5
53
66
69.5
79.5
107
173
79.5
89.5
147
320
89.5
99.5
130
450
EXA MP L E OF A FREQ UENCY
P O LY G O N
F R E Q U E N C Y P O LY G O N S F O R
G R O U P E D D ATA
A...
...travelers are asked which midwestern city they prefer: Indianapolis, Saint Louis, Chicago, or Milwaukee. 120 liked Indianapolis best, 430 liked Saint Louis, 1360 liked Chicago, and the remainder preferred Milwaukee. Develop a frequency table and a relative frequency table to summarize this information. (Round relative frequency to 3 decimal places.) 
City  Frequency  Relative Frequency 
Indianapolis  120  0.060 
St. Louis  430  0.215 
Chicago  1,360  0.680 
Milwaukee  90  0.045 

(a)  What is this chart called? 
 
 Histogram 
(b)  What is the total number of frequencies? 
 
 100 
(c)  What is the class interval? 
 
 5 
(d)  What is the class frequency for the 25 to 30 class? 
 
 10 
(e)  What is the relative frequency of the 25 up to 30 class? (Round your answer to 2 decimal places.) 
 
 .10 
(f)  What is the midpoint of the 15 up to 20 class? (Round your answer to 1 decimal place.) 
 
 17.5 
(g)  On how many days were there 10 or more packages shipped? 
 
 5 
award:
12.50 out of
16.66 points
The following frequencydistribution reports the number of frequent flier miles, reported in...
...Statistics1
1. One thousand candidates sit an examination. The distribution of marks is shown in the following grouped frequency table.
Marks1–1011–2021–3031–4041–5051–6061–7071–8081–9091–100
Number of candidates155010017026022090453020
(a) Copy and complete the following table, which presents the above data as a cumulative frequencydistribution.
(3)
Mark£10£20£30£40£50£60£70£80£90£100
Number of candidates1565905
(b) Draw a cumulative frequency graph of the distribution, using a scale of 1 cm for 100 candidates on the vertical axis and 1 cm for 10 marks on the horizontal axis.
(5)
(c) Use your graph to answer parts (i)–(iii) below,
(i) Find an estimate for the median score.
(2)
(ii) Candidates who scored less than 35 were required to retake the examination.
How many candidates had to retake?
(3)
(iii) The highestscoring 15% of candidates were awarded a distinction.
Find the mark above which a distinction was awarded.
(3)
(Total 16 marks)
2. At a conference of 100 mathematicians there are 72 men and 28 women. The men have a mean height of 1.79 m and the women have a mean height of 1.62 m. Find the mean height of the 100 mathematicians.
(Total 4 marks)
3. The mean of the population x1, x2, ........ , x25 is m. Given that = 300 and
= 625, find
(a) the value of m;
(b) the standard deviation of the population....
...illustrate trends, etc.
TO ADVOCATE AN ISSUE
TO SHOW THE STATUS OF AN INDICATOR
TO COMPARE INDICATORS
TO DEMONSTRATE CORRELATIONS
TO ILLUSTRATE TRENDS
INFOGRAPHICS USING EXCEL
Frequency Tables and Histograms Charts : create and format charts Conditional Formatting Sparklines Excel Graphics
FREQUENCYDISTRIBUTION
Shows how many observations fall in various categories(bins) Can be represented in a Frequency Table To obtain a Frequency Table for any given data, we must first choose appropriate number of bins Each bin defines a “slot” where some values may fall in There is no set rule for choosing no of bins (good practice is 8 to 15) Need enough categories to get a meaningful distribution, but too many categories will result in few observations per category
A FREQUENCY TABLE OF MARKS OBTAINED
Mark Range (Bins) 12 34 56 78 910
Frequency
2 15 25 18 5
HISTOGRAM
A histogram is the graphical analog of a frequency table Histograms show the frequency with which various category/bin values appears in the data set (e.g., how many students received marks between 2 and 3) The Xaxis of a histogram shows the possible categories and the Yaxis show the frequency
CREATING A HISTOGRAM IN EXCEL
Identify the bins, and define bin range Create Frequency Table and...
...Letter frequency
From Wikipedia, the free encyclopedia
The most common letter in the English alphabet is E. The frequency of letters in text has often been studied for use in cryptography, and frequency analysis in particular. No exact letter frequencydistribution underlies a given language, since all writers write slightly differently. Linotype machines assumed the letter order, from most to least common, to be etaoin shrdlu cmfwyp vbgkjq xz based on the experience and custom of manual compositors. Likewise, Modern International Morse code encodes the most frequent letters with the shortest symbols; arranging the Morse alphabet into groups of letters that require equal amounts of time to transmit, and then sorting these groups in increasing order, yields e it san hurdm wgvlfbk opjxcz yq. Similar ideas are used in modern datacompression techniques such as Huffman coding.
Contents
[hide]
1 Introduction
2 Relative frequencies of letters in the English language
3 Relative frequencies of the first letters of a word in the English language
4 Relative frequencies of letters in other languages
5 See also
6 References
7 External links
Introduction[edit source  editbeta]
More recent[when?] analyses show that letter frequencies, like word frequencies, tend to vary, both by writer and by subject. One cannot write an essay about...