# 2.1 Stem-and-leaf graphs (stemplots), line graphs, and bar graphs  (Page 3/5)

 Page 3 / 5

## Try it

The population in Park City is made up of children, working-age adults, and retirees. [link] shows the three age groups, the number of people in the town from each age group, and the proportion (%) of people in each age group. Construct a bar graph showing the proportions.

Age groups Number of people Proportion of population
Children 67,059 19%
Retirees 131,662 38%

The columns in [link] contain: the race or ethnicity of students in U.S. Public Schools for the class of 2011, percentages for the Advanced Placement examine population for that class, and percentages for the overall student population. Create a bar graph with the student race or ethnicity (qualitative data) on the x -axis, and the Advanced Placement examinee population percentages on the y -axis.

Race/Ethnicity AP Examinee Population Overall Student Population
1 = Asian, Asian American or Pacific Islander 10.3% 5.7%
2 = Black or African American 9.0% 14.7%
3 = Hispanic or Latino 17.0% 17.6%
4 = American Indian or Alaska Native 0.6% 1.1%
5 = White 57.1% 59.2%
6 = Not reported/other 6.0% 1.7%

## Try it

Park city is broken down into six voting districts. The table shows the percent of the total registered voter population that lives in each district as well as the percent total of the entire population that lives in each district. Construct a bar graph that shows the registered voter population by district.

District Registered voter population Overall city population
1 15.5% 19.4%
2 12.2% 15.6%
3 9.8% 9.0%
4 17.4% 18.5%
5 22.8% 20.7%
6 22.3% 16.8%

## References

Burbary, Ken. Facebook Demographics Revisited – 2001 Statistics, 2011. Available online at http://www.kenburbary.com/2011/03/facebook-demographics-revisited-2011-statistics-2/ (accessed August 21, 2013).

“9th Annual AP Report to the Nation.” CollegeBoard, 2013. Available online at http://apreport.collegeboard.org/goals-and-findings/promoting-equity (accessed September 13, 2013).

“Overweight and Obesity: Adult Obesity Facts.” Centers for Disease Control and Prevention. Available online at http://www.cdc.gov/obesity/data/adult.html (accessed September 13, 2013).

## Chapter review

A stem-and-leaf plot is a way to plot data and look at the distribution. In a stem-and-leaf plot, all data values within a class are visible. The advantage in a stem-and-leaf plot is that all values are listed, unlike a histogram, which gives classes of data values. A line graph is often used to represent a set of data values in which a quantity varies with time. These graphs are useful for finding trends. That is, finding a general pattern in data sets including temperature, sales, employment, company profit or cost over a period of time. A bar graph is a chart that uses either horizontal or vertical bars to show comparisons among categories. One axis of the chart shows the specific categories being compared, and the other axis represents a discrete value. Some bar graphs present bars clustered in groups of more than one (grouped bar graphs), and others show the bars divided into subparts to show cumulative effect (stacked bar graphs). Bar graphs are especially useful when categorical data is being used.

For each of the following data sets, create a stem plot and identify any outliers.

The miles per gallon rating for 30 cars are shown below (lowest to highest).
19, 19, 19, 20, 21, 21, 25, 25, 25, 26, 26, 28, 29, 31, 31, 32, 32, 33, 34, 35, 36, 37, 37, 38, 38, 38, 38, 41, 43, 43

Stem Leaf
1 9 9 9
2 0 1 1 5 5 5 6 6 8 9
3 1 1 2 2 3 4 5 6 7 7 8 8 8 8
4 1 3 3

The height in feet of 25 trees is shown below (lowest to highest).
25, 27, 33, 34, 34, 34, 35, 37, 37, 38, 39, 39, 39, 40, 41, 45, 46, 47, 49, 50, 50, 53, 53, 54, 54

The data are the prices of different laptops at an electronics store. Round each value to the nearest ten.
249, 249, 260, 265, 265, 280, 299, 299, 309, 319, 325, 326, 350, 350, 350, 365, 369, 389, 409, 459, 489, 559, 569, 570, 610

Stem Leaf
2 5 5 6 7 7 8
3 0 0 1 2 3 3 5 5 5 7 7 9
4 1 6 9
5 6 7 7
6 1

The data are daily high temperatures in a town for one month.
61, 61, 62, 64, 66, 67, 67, 67, 68, 69, 70, 70, 70, 71, 71, 72, 74, 74, 74, 75, 75, 75, 76, 76, 77, 78, 78, 79, 79, 95

For the next three exercises, use the data to construct a line graph.

In a survey, 40 people were asked how many times they visited a store before making a major purchase. The results are shown in [link] .

Number of times in store Frequency
1 4
2 10
3 16
4 6
5 4

In a survey, several people were asked how many years it has been since they purchased a mattress. The results are shown in [link] .

Years since last purchase Frequency
0 2
1 8
2 13
3 22
4 16
5 9

Several children were asked how many TV shows they watch each day. The results of the survey are shown in [link] .

Number of TV Shows Frequency
0 12
1 18
2 36
3 7
4 2

The students in Ms. Ramirez’s math class have birthdays in each of the four seasons. [link] shows the four seasons, the number of students who have birthdays in each season, and the percentage (%) of students in each group. Construct a bar graph showing the number of students.

Seasons Number of students Proportion of population
Spring 8 24%
Summer 9 26%
Autumn 11 32%
Winter 6 18%

Using the data from Mrs. Ramirez’s math class supplied in [link] , construct a bar graph showing the percentages.

David County has six high schools. Each school sent students to participate in a county-wide science competition. [link] shows the percentage breakdown of competitors from each school, and the percentage of the entire student population of the county that goes to each school. Construct a bar graph that shows the population percentage of competitors from each school.

High School Science competition population Overall student population
Alabaster 28.9% 8.6%
Concordia 7.6% 23.2%
Genoa 12.1% 15.0%
Mocksville 18.5% 14.3%
Tynneson 24.2% 10.1%
West End 8.7% 28.8%

Use the data from the David County science competition supplied in [link] . Construct a bar graph that shows the county-wide population percentage of students at each school.

line y=a+bx for curve fitting is what?
y=a+bx is use to fit a straight line
Dillu
thx
Elrin
I didn't find ur question send again if I know I will answer
Dillu
where can i send it
Elrin
do u have an email
Elrin
send in this question box
Dillu
1. There is some evidence that REM sleep, associated with dreaming, may also play a role in learning and memory processing. For example, Smith and Lapp (1991) found increased REM activity for college students during exam periods. Suppose that REM activity for a sample of n=6 students during the
Elrin
nevermind
Elrin
sry I don't have clear answer fr this
Dillu
so, like you have bagA of 5red balls and 2 white balls and bagB of 4red balls and 6white balls,if a ball is picked up randomly from each bag, what's the probability that both will be different colors
what is questionnaire
list of simple and short questions asked to collect primary data
Atul
ok tnx
Akinwale
what is data science?
Aminu
data science is the study of data. It involves developing methods of recording, storing, and analyzing data to effectively extract useful information.
Akinwale
What is attribute?
Atul
what is mode?
Arnab
value with highest frequency in data set
Atul
what is data mining?
Aminu
Data mining is a process used by companies to turn raw data into useful information. By using software to look for patterns in large batches of data.
Akinwale
what is data analytics?
Aminu
a study of potential age discrimination considers promotion among middle managers in a large company...
how do we know to set null hypothesis
This is Statistic information
Thank average daily sales of a shopkeeper is Rs 200 with a standard deviation Rs 40 for how many days in a leap years his sales are exacted to be worth 1. less than Rs 150 and 2. over Rs 300 ?
what is the probability of at least one in "H"in three tosses of coin?
150%
Andrew
Sorry... 1-(.5^3)=7/8
Andrew
but how?
aneeza
1-(7/8)=1/8 total 8 out comes will appear in that "H" will appear in 7 times that's way
Dillu
sorry ... 1- (probability of getting no heads)=1-(1/8)=7/8
Dillu
HHH.HHT.HTH.THH.HHT.TTH.HTT=7 probability will 7/8
Atul
1-(3C0)(1/2)^3
Chitran
sorry probability has been my worst nightmare can you just break down the equation on how you solve it to give you 7/8
Vernissa
do you think that concurrent method of correlation describe any realtionship between supply and index in data given. supply 112,125,126,118,121,12 price 106,102,102,104,98
X 77 54 27 52 14 35 90 25 Y 35 38 60 40 35 56 34 50
Given the distribution X ~ U (2, 8)
minutes to drive from her suburban home to her midtown office.
Bilal
Define suitable populations from which the following samples are selected Persons in 200 homes are called by telephone in the city of Richmond & asked to name the candidate that they favor for election to the school board. On 5 different occasions it took a lawyer 21, 26, 24, 22 & 21 minutes to
Bilal
Define suitable populations from which the following samples are selected Persons in 200 homes are called by telephone in the city of Richmond & asked to name the candidate that they favor for election to the school board.
Bilal
first one is discrete population with more than two options so it should be multinomial population in second question variable is time so it's a continuous dist, and time is normally distributed so it is normal
fitting of regression equation
how to solve exercise to find difference between HoandHa
Give the info....
Andrew
What is Sampling Techniques?
What is Sampling frame
Goodness
what is stratified Sampling
Goodness
This Sampling technique uses randomization to make sure that every element of the population gets an equal chance to be part of the selected sample. It’s alternatively known as random sampling.
Biswajit
When we take a sample from a population and use a methods for sampling, that mathos are known as sampling technique.
Zahir
why we use distribution in statstics?
Biswajit
Sampling frame is the overall list of population, from which we take sample.
Zahir
The distribution of a statistical data set is a listing or function showing all the possible values (or intervals) of the data and how often they occur.
Zahir
what is statistics
lokesh
Goodness, what's your field of study?
Afrifa
Thanks you
Shakeel
fs>2fm
Teja
sampling techniques are used to convert analog signal into discrete forms which means encode
Teja
Given the distribution X ~ U (2, 8)
KATHY
enumerate main sources of errors in statistics and effects
Bilal
when we divide heterogeneous population into homogeneous sun groups and sample it we called it stratified sampling
Keshav
**sub
Keshav
what are heterogeneous and homogeneous population
helen
Principles of research data
Define statistical distribution of data set?
Sodium