Chapter 4 - Displaying and Summarizing Quantitative Data

1) Bar graphs are used to display categorical data, while histograms are used to display quantitative data. Also, bars do NOT touch in bar graphs, but they do touch in histograms.

2a) When you describe a distribution, you should ALWAYS tell about three things: its shape, center, and spread.

2b) While talking about the shape of a distribution you should look if the histogram has any humps, or in other words modes. A histogram with one peak is called unimodal,  histograms with two peaks are called bimodal, and histograms with three or more are called multimodal. Another thing to look for is to see if the histogram is symmetric, if there are any outliers that stand ot from the rest of the data, and  notice if the histogram is skewed either to the right or left.

The center of the distribution can either be literally at the center of the distribution if it is unimodal symmetrical distribution, but if not it is known as the median, which is the middle value that divides the histogram into two equal areas.

When talking about the spread of the data it is important to note the range of the data, which is defined as the difference between the maximum and minimum values. The interquartile range (IQR) is the difference between the upper quartile and lower quaritile that tells us how much territory the middle half of the data covers.

3) Average Height by Teenagers by frequency
a)  5 Number Summary:
       Max: 8
       Q3:
       Median:
      Q1:
      Min.:

3b) Mean:
Standard Deviation:

3c)  

The graph appears to be unimodal,as it has one peak at 130 to 134. The graph also appears to be symmetrical because if we were to fold it in half it would match up appropriately.

Chapter 3- Displaying and Describing Categorical Data

1)

APA Citation: Global Religious Diversity. (2014, April 4). Retrieved August 9, 2014, from http://www.pewforum.org/2014/04/04/global-religious-diversity/

 a) Yes the graph is clearly labeled as it shows the percentage of major religious groups throughout the globe.

b) The area principle says that the area occupied by a part of the graph should correspond to the magnitude of the value it represents.This graph DOES NOT violate the area principle as everything is proportional and the percentages add up to 100%.
c) The article does provide the W's of the variable.
Who: The entire global population
What: Major religious groups
When: 2010
Where: N/A
Why: To show the diverse religion groups that the majority of the world practices.
d) Yes, I believe the article correctly interprets the data correctly. The largest countries in the world reside in Asia and Europe, which would explain why they are the most religiously diverse in the world.

2)

APA Citation: Saad, L. (2014, June 27). More in U.S. Would Decrease Immigration Than Increase. Retrieved August 9, 2014, from http://www.gallup.com/poll/171962/decrease-immigration-increase.aspx

a) Yes, the graph is clearly labeled.
b) This graph displays percentages.
c) Yes the accompanying article tells us the W's of the variable.
Who: National adults, republicans, independents, and democrats.
When: Conducted June 5-8, 2014
Why: To see how Americans feel about immigration, whether it should be increased, decreased, or kept at the present level.
d) Yes, I believe the article correctly interprets the data. The article goes into depth of some of the reasoning behind the responses of Americans.
3)

Link: http://www.pewinternet.org/2014/04/03/older-adults-and-technology-use/

a) Yes, the graph is clearly labeled.

b) No, the graph does NOT violate the area principle. The length of the bars are proportional to the values.

c) The variables under consideration are the age groups because there are no units available. The accompanying article does not give us all the W's of the variables, but you are able to retrieve them from the graph.

What: Number of times they use the internet

Who: Different age groups

When: Conducted from July 18- September 30, 2013

Where: N/A

Why: To compare how different age groups differ in the amount of time they spend on the internet

d) I believe the article correctly interprets the data. The article states that older adults who use the internet, make it a habit to visit it almost every day. The graph supports this as it shows that 71% of adults 65 years and older use the internet almost every day.

Chapter 2 - Data

1) The two questions which must be answerable if you are to actually have data are Who and What. Some additional questions that should be answered to provide context for the data you may be working with are When, Where, Why, and How.
2) Categorical Variable: When a variable names categories and answers questions about how cases fall into those categories.
Quantitative Variable: When a measured variable with units answers questions about the quantity of what is measured.
Case: an individual who we collect data on.
Sample: a selected portion that is used to show what the whole portion is like.
Population: the whole array of cases we wish we knew about.
An example of a categorical variable would be a survey about which frozen yogurt you prefer the most. The case would be the specific frozen yogurt you chose. The sample would be the data specifically on the frozen yogurt you chose. The population would be all the frozen yogurts you surveyed from.

An example of a quantitative variable would be the average weight in the United States for all ages. A case would be a person in specific, in example a close friend. A sample would be only the average weight of females ages 12-16. The population could be the average weight in the entire U.S.
3)

Total tuition, room and board rates charged for full-time undergraduate students in degree-granting institutions for 1 year of college.
Year	All Institutions	4-Year Institutions	2-Year Institutions
2012–2013	$19,344	$22,261	$9,180
2010–11	$18,497	$22,092	$8,909
2009–10	17,649	21,093	8,533
2008–09	17,092	20,409	8,238
2007–08	16,231	19,363	7,637
2006–07	15,483	18,471	7,466
2005–06	14,634	17,451	7,236
2004–05	13,793	16,510	7,095
2003–04	12,953	15,505	6,705
2002–03	12,014	14,439	6,252
2001–02	11,380	13,639	5,718
2000–01	10,820	12,922	5,466
1990–91	6,562	7,602	3,930
1980–81	3,101	3,499	2,230

A) URL: http://www.statisticbrain.com/average-cost-of-college-tuition/

B) I know that I have data because I am able to answer the Who and What questions. 

Who: Average cost of college including total tuition, room and board rates charged for full-time undergraduate students in degree-granting institutions for 1 year of college.

What: Year, all institutions, 4-year institutions, and 2-year institutions. 

C) When: 1980-2013 

Where: The United States 

Why: To calculate what the average cost of college tuition a year is.

How: Through the U.S Department of Education, National Center for Education Statistics

D) Year is categorical, all institutions is categorical, 4-year institutions is categorical, and 2-categorical.