This is an R Markdown document. Markdown is a simple formatting syntax for authoring HTML, PDF, and MS Word documents. For more details on using R Markdown see http://rmarkdown.rstudio.com.

When you click the Knit button a document will be generated that includes both content as well as the output of any embedded R code chunks within the document. You can embed an R code chunk like this:

Distribution

Reading 2.1, problems => 7 - 15 odds, due Sep 16th

7. Top 10 Internet Users: The following Pareto chart represents Internet users in the top 10 countries as of June 2010.

  1. Which country had the most Internet users in 2010? China
  2. Approximately how many Internet users did the United Kingdom have in 2010? 50 Million Users
  3. Approximately how many more users were in China than in Germany in 2010? 350 Million More Users
  4. How might this graph be misleading? Accessibility and Population Size: Relative Frequency Was Not Used

9. Divorce: The following graph represents the results of a survey, conducted in May 2010, in which a random sample of adult Americans was asked, “Please tell me whether you personally believe that in general divorce is morally acceptable or morally wrong.”

  1. What percent of the respondents believe divorce is morally acceptable? Est 70%
  2. If there were 240 million adult Americans in 2010, how many believe that divorce is morally wrong? 48 Million believe divorce is morraly wrong
  3. If Gallup claimed that the results of the survey indicate that 8% of adult Americans believe that divorce is acceptable in certain situations, would you say this statement is descriptive or inferential? Why? The study of the sample was observational: I would say Inferrential

11. Made in America: In a poll conducted July 27–29, 2010, a random sample of 2163 adults (aged 18 and over) was asked, “When you see an ad emphasizing that a product is ‘Made in America’, are you more likely to buy it, less likely to buy it, or neither more nor less likely to buy it?” The results of the survey are presented in the side-by-side bar graph.

  1. What proportion of 18 to 34 year old respondents are more likely to buy when made in America? What proportion of 35 to 44 year old respondents are more likely to buy when made America? 45% for the first sample and 60% for the second sample
  2. Which age group has the greatest proportion who are more likely to buy when made in America? 55 and older are more likely to buy “Made In the USA”
  3. Which age group has a majority of respondents who are less likely to buy when made in America? 18 to 34
  4. What is the apparent association between age and likelihood to buy when made in America? The older demographic are more likey to buy American made goods than the younger demographic: The increase in age makes it more likely

13. College Survey: (Need Help With The Process) In a national survey conducted by the Centers for Disease Control to determine health-risk behaviors among college students, college students were asked, “How often do you wear a seat belt when riding in a car driven by someone else?” The frequencies were as follows:

  1. Construct a relative frequency distribution. Never .20, Rarely .40, Sometimes .60, Most of the time .80, Always 1.0
  2. What percentage of respondents answered “Always”? 52%
  3. What percentage of respondents answered “Never” or “Rarely”?
  4. Construct a frequency bar graph.
  5. Construct a relative frequency bar graph.
  6. Construct a pie chart.
  7. Suppose that a representative from the Centers for Disease Control says,“52.7% of all college students always wear a seat belt.” Is this a descriptive or inferential statement?

15. Use the Internet? (Need Help With The Process) The Gallup organization conducted a survey in which 1025 randomly sampled adult Americans were asked, “How much time, if at all, do you personally spend using the Internet—more than 1 hour a day, up to 1 hour a day, a few times a week, a few times a month or less, or never?” The results of the survey were as follows:

  1. Construct a relative frequency distribution.
  2. What proportion of those surveyed never use the Internet?
  3. Construct a frequency bar graph.
  4. Construct a relative frequency bar graph.
  5. Construct a pie chart.
  6. A local news broadcast reported that 37% of adult Americans use the Internet more than 1 hour a day. What is wrong with this statement?

Reading 2.2, problems => 9 - 16, due Sep 16th

9. Rolling the Dice: An experiment was conducted in which two fair dice were thrown 100 times. The sum of the pips showing on the dice was then recorded. The following frequency histogram gives the results.

  1. What was the most frequent outcome of the experiment? 8
  2. What was the least frequent? 2
  3. How many times did we observe a 7? Frequency of 15
  4. How many more 5’s were observed than 4’s? 4 more est
  5. Determine the percentage of time a 7 was observed. 13%
  6. Describe the shape of the distribution. Bell shaped

10. Car Sales: A car salesman records the number of cars he sold each week for the past year. The following frequency histogram shows the results.

  1. What is the most frequent number of cars sold in a week? 4 cars
  2. For how many weeks were two cars sold? 9 weeks
  3. Determinethepercentageoftimetwocarsweresold. 15%
  4. Describe the shape of the distribution. Leans Right

11. IQ Scores: The following frequency histogram represents the IQ scores of a random sample of seventh-grade students. IQs are measured to the nearest whole number. The frequency of each class is labeled above each rectangle.

  1. How many students were sampled? 200
  2. Determine the class width. 60 to 160
  3. Identify the classes and their frequencies. IQ scores are the classes
  4. Which class has the highest frequency? 100 to 110 has the highest frequency
  5. Which class has the lowest frequency? 150 to 160 has the lowest frequency
  6. What percent of students had an IQ of at least 130? 94%
  7. Did any students have an IQ of 165? Zero Value

12. Alcohol-Related Traffic Fatalities: The frequency histogram in the next column represents the number of alcohol-related traffic fatalities by state (including Washington, D.C.) in 2008 according to the National Highway Traffic Safety Administration.

  1. Determine the class width.
  2. Identify the classes. number of fatalities per state
  3. Which class has the highest frequency? 0 to 200 has the highest
  4. Describe the shape of the distribution. Leans right
  5. A reporter writes the following statement: “According to the data, Texas had 1463 alcohol-related deaths, while Vermont had only 15. So the roads in Vermont are much safer.” Explain what is wrong with this statement and how a fair comparison can be made between alcohol-related traffic fatalities in Texas versus Vermont. Texas has a larger population than Vermont which in turn means more drivers + higher frequency

In Problems 13 and 14, for each variable presented, state whether you would expect a histogram of the data to be bell-shaped, uniform, skewed left, or skewed right. Justify your reasoning.

  1. Annual household incomes in the United States Leans right, lowest to highest income
  2. Scores on a standardized exam such as the SAT Bell shape
  3. Number of people living in a household Uniform
  4. Ages of patients diagnosed with Alzheimer’s disease Leans lesft, younger population would be less likely to have Alzheimers
  1. Number of alcoholic drinks consumed per week (b) Ages of students in a public school district Leans right, youngest to oldest
  2. Ages of hearing-aid patients Leans left, with the older population be more likely to be hearing aid patients
  3. Heights of full-grown men Uniform