# 1.2 Data, sampling, and variation in data and sampling  (Page 3/56)

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Fall term 2007 (census day)
De Anza College Foothill College
Number Percent Number Percent
Full-time 9,200 40.9% Full-time 4,059 28.6%
Part-time 13,296 59.1% Part-time 10,124 71.4%
Total 22,496 100% Total 14,183 100%

Tables are a good way of organizing and displaying data. But graphs can be even more helpful in understanding the data. There are no strict rules concerning which graphs to use. Two graphs that are used to display qualitative data are pie charts and bar graphs.

In a pie chart , categories of data are represented by wedges in a circle and are proportional in size to the percent of individuals in each category.

In a bar graph , the length of the bar for each category is proportional to the number or percent of individuals in each category. Bars may be vertical or horizontal.

A Pareto chart consists of bars that are sorted into order by category size (largest to smallest).

Look at [link] and [link] and determine which graph (pie or bar) you think displays the comparisons better.

It is a good idea to look at a variety of graphs to see which is the most helpful in displaying the data. We might make different choices of what we think is the “best” graph depending on the data and the context. Our choice also depends on what we are using the data for.

## Percentages that add to more (or less) than 100%

Sometimes percentages add up to be more than 100% (or less than 100%). In the graph, the percentages add to more than 100% because students can be in more than one category. A bar graph is appropriate to compare the relative size of the categories. A pie chart cannot be used. It also could not be used if the percentages added to less than 100%.

De anza college spring 2010
Characteristic/Category Percent
Full-Time Students 40.9%
Students who intend to transfer to a 4-year educational institution 48.6%
Students under age 25 61.0%
TOTAL 150.5%

## Omitting categories/missing data

The table displays Ethnicity of Students but is missing the "Other/Unknown" category. This category contains people who did not feel they fit into any of the ethnicity categories or declined to respond. Notice that the frequencies do not add up to the total number of students. In this situation, create a bar graph and not a pie chart.

Ethnicity of students at de anza college fall term 2007 (census day)
Frequency Percent
Asian 8,794 36.1%
Black 1,412 5.8%
Filipino 1,298 5.3%
Hispanic 4,180 17.1%
Native American 146 0.6%
Pacific Islander 236 1.0%
White 5,978 24.5%
TOTAL 22,044 out of 24,382 90.4% out of 100%

The following graph is the same as the previous graph but the “Other/Unknown” percent (9.6%) has been included. The “Other/Unknown” category is large compared to some of the other categories (Native American, 0.6%, Pacific Islander 1.0%). This is important to know when we think about what the data are telling us.

This particular bar graph in [link] can be difficult to understand visually. The graph in [link] is a Pareto chart. The Pareto chart has the bars sorted from largest to smallest and is easier to read and interpret.

why we calculate mean?
pls I need more of statistics materials
Ali
According to my understanding, statistics are numerical data or information presented in charts or graphs
thanks
Said
what is statistics
how to find critical angle
what is statistics ?
Statistics is deal with the collection, analysis, interpretation, presentation of data to drawn out conclusions.
Ajao
collection presentation analysis interpretation Kia he sir
In my own perspective statistics is deal with the collection, analysis, interpretation, presentation of data before will drawn our conclusions
Ajao
thank you sir pragaph bejo
In simple way it is the technique of problem solving by providing probabilistic answer to questions otherwise whose exact answer is not possible..besides it is the support to every subject you study.
being
data
Deng
Data is information that has been translated into a form that is efficient for movement or processing
Mansour
group the scores below into a class interval of seven and obtain the following: 1.. i..class interval ii..tally iii..frequency iv..mid point v...cummulative frequency less than vi..cummulative frequency more than vii..relative frequency viii...relative percentage
Icecool
2..draw a histogram and frequency polygon to sick it the statistical table
Icecool
20,30,39,25,50,26,39,32,43,20,30,40,50,10,16,12,19,31,32,26,29,27,28,42,63,48,11,26,35,36,37,38,39,39,35,29,53,37,32,24,36,43,48,42,51,37,39,39,24,7,8,13,62,52,69,68,37,38,39,40,41,39,54
Icecool
2.draw a histogram and frequency polygon to sick it the statistical
Deng
2.draw a histogram and frequency polygon to dipict the statistical table
Icecool
Describe the organizational setup of bureau of statics government of sindh give its past achievement in brief
Life Table and its construction
Awais
only asking what is hospital statistics
What's the meaning Of statistic
what's the meaning of statistic
Musa
The mean is the average of the numbers. It is easy to calculate: add up all the numbers, then divide by how many numbers there are. In other words it is the sum divided by the count.
pls I want to know the characterize of mean
I want solution to; x,x+1,3.5,3.4 and 2.5 is 3.1. find the value of x
Trixie
mean is nothing but average.
NAMDEV
(x+x+1+3.5+3.4+2.5)/5=3.1 2x+10.4=3.1*5 x=(15.5-10.4)/2 x=2.55
NAMDEV
How. Pls explain or break it down thanks
Icecool
the sum of all five divided by the 5 which is the average is equal to 3.1 so you sum them, divide and equate to 3.1. then solve for X by making X the subject
Pascale
Think of it as your grade, or gpa. how do you find the average of it?
La
great
Rushikesh
nicely explained
Rushikesh
What is the meaning of statistics and it's relevance in the social sciences
statistics is the branch of mathematics that using math& statistics theories to interpret data to information which is supporting the decision makers in social sciences and applied too. statistics is decision making science now aday
Ishag
I want to slove this math
I'm not seeing the Math problem?
Debra
the data below where from 1 miles. miles 1:8380, 8210,3836,7840,7910,7510,7720,7750,8100,7690 test wherever their difference is significance at 5% level with population of #8000.
Enny
1*1
Enny
me too
New
enny i don't see any math problems
New
hello my friend. how can you help me to solve math
ott
help me the interquartile range and semi interquartile range of grouped data
Ishraaq
what is the difference between macro and micro data?
Macrodata consist of 'headcounts', Microdata contain data on individuals,
Cherry
Mukhtar
macro means whole or big and micro means part or small therefore in relation to data, macro data will be big or whole data and micro data will be small or individual part of a data. for example taking the whole data of an organisation or economy that will be macro data and taking the data on employe
Pascale
employees will be micro data
Pascale
How to determine appropriate statistics tool for my data
hi
Juliana
hi
Emy
You cannot know everything! Statistics is a vast subject so don’t be afraid to say that you don’t know. Ask others for help or look up information on the internet to help. Don’t assume that the student knows anything about the technique they are suggesting!
Kalu
well
Tahir
my class starts at February 4th
Elaine
P is the probability that a given die shows even number. To test H0 : P =1/2 against H1 : P=1/3, following procedure is adopted. Toss the die twice and accept H0 if both times it shows even number. Find the probabilities of type I and type II errors
what is statistics?
what is data
natnael
It Is the collection, collation,Analysing Interpretation,and presentation of data....
Tosayo
statistics is a science that studies numerical values assigned to objects, attributes or variables in order to characterize and make the variables more meaningful.
Okosa
statistics is the science of collection, analysis, Interpretation & presentation of numerical data
Kishan
Numeric data
Tosayo
if you think about normal number and operations of math such as fractions and percent values, statisitics is when it comes down to it a lot of just that - counting and then fractions, then that data and those counts (and ratios)/fractions that were used or counted in one group will represent a pop.
Jesus
An example is, lets say you are in charge of making large orders of supplies and that based on your need of X bricks = X feet of building - now thats the math, well stats is using that math in a way the next person making orders can base those orders of what they will need based on saying "in this
Jesus
..case, when Bilal needed 75 feet of building walls that 150 bricks were used" - now, that helps to get one job done but if we then watch those jobs one at a time, and count that 5/5 times the count was 150 bricks total - the new person could order 150 bricks with a high probability of being right
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