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Things to Think About….1. Are all the responses words? 2. Are any responses numbers? 2. Do any responses seem strange? Not valid?3. Any data I should eliminate? Not count?4. Does the data make sense? Not make sense? 4. Any common patterns or conclusions? 5. How can I display or summarize this data?6. What type of title can I have for this data?7. Do you think this is a good way to collect data?*These are all topics we are going to discuss in Chapter 1*
And all that is ….STATISTICS!!-Ask a question of Interest-Produce Data-Analyze Results-Interpret Results(this class will go into detail for all these areas)
Today we will begin Chapter 1….Chapter 1“Statistics : The Art and Science of Data”Textbook pages 1-301.1 Where do Data Come from?1.2 Drawing Conclusions from Data?
Section 1.1 Statistics: The Art and Science of Data Where Do Data Come From?(starts on page 2 of the textbook)
What is Data? • Data is a collection of information in context. • Want some data facts? Go to snapple.com • How do you think the data was produced? • How did they determine this?
More Data Examples –Textbook page 2 • In 2007, 12.5% of drivers involved in fatal crashes were 15-20 years old. https://www.nhtsa.gov/sites/nhtsa.dot.gov/files/810888graddriverlicense_0.pdf • 51% of U.S. adults engage in “vigorous exercise” at least once a week. • Taking aspirin regularly reduces the risk of a heart attack. Where do these data come from? Can we trust them?
Where do data come from? • “Where do data come from?” is the first question you should ask when you hear a statistic. Remember: • Good data are the product of intelligent human effort. • Bad data results from laziness, lack of understanding or the desire to mislead others.
What about personal experiences? • It is tempting to base conclusions on your own experiences. • But our own experiences may not be typical. In fact, the incidents that stick in our memory are often unusual. • We are much safer relying on carefully produced data.
Personal Experience ExampleTextbook page 3-Do cell phones cause brain cancer? • In August 2000, Dr. Chris Newman, a frequent cell phone user developed brain cancer. • His physician suggested that his brain tumor may have been caused by cell phone use. • He sued Motorola and Verizon. As people heard about his story, they began to worry about whether cell phone use can lead to cancer. • According to many studies, there are no association between these two variables but yet people are still convinced Dr. Newman’s experience is typical. Cellular Telephone Use and Cancer Risk:
What is Statistics? • Statistics is the study of data collection and analysis. • Used to make predictions or conclusions. • Statistics are made on individuals and organized into variables. (found on page 3 in textbook)
Terms • Individuals: objects described by a set of data. (e.g. people, animals, things) • Variable: any characteristic of these individuals (e.g. eye color, height, test score) (found on page 3 in textbook)
Example • In our class survey the Individuals are: • The Variables are: *Note: Not all variables are numbers
Two types of Variables • Categorical Variable:places data into one of several groups or categories. (male or female, types of cars, birth month) • Quantitative variable: takes numerical values. (number of goals scored by a team, number of siblings, height, weight, GPA, ) • What are some examples of each of our data?? (found on page 4 in textbook)
Types of Graphs • Bar graph and Pie Chart: good for categorical variables • Histograms, Dot Plots, Time Plots, and Stemplots: good for quantitative variables.
Example-Students in a Stat Class What individuals does this data set describe? For each individual, what variables are given? Identify each variable as categorical or quantitative. (found on page 5 in textbook)
Exercise 1 In the NBA, the fans vote to decide which player get to play in the NBA All-Star Game. Kevin Garnett of the Boston Celtics led all players, with 2,399,148 votes for the 2008 All-Star Game. The table below provides data about the top five vote-getters that year. (a)What individuals are measured?
Exercise 1 In the NBA, the fans vote to decide which player get to play in the NBA All-Star Game. Kevin Garnett of the Boston Celtics led all players, with 2,399,148 votes for the 2008 All-Star Game. The table below provides data about the top five vote-getters that year. (b) What variables are recorded??
Exercise 1 In the NBA, the fans vote to decide which player get to play in the NBA All-Star Game. Kevin Garnett of the Boston Celtics led all players, with 2,399,148 votes for the 2008 All-Star Game. The table below provides data about the top five vote-getters that year. (b) What variables are recorded??
Exercise 1 (b) Quantitative or Categorical? In what units is each quantitative variable recorded? Team Votes PPG Height Position
Do Now • Please take two pieces of paper from the front desk. • In BLUE, write down 2 examples of a CATEGORICAL Variable • In RED, write down 2 examples of a QUANTITATIVE Variable • Place each piece of paper in their respective half of the side white board. (Try not to use the same variables as those around you so we have a little variety )
Terms • Observational study: a study that observes individuals and measures variables of interest but does not attempt to influence the responses. • Population: the entire group of individuals about which we want information or to make predictions about. • Sample: a part of the population from which we actually collect information, which is then used to draw conclusions about the whole. • Individual: a member of the population Time for a break-kahoot (found on page 6-7 in textbook)
Terms • Sample surveys: measure characteristics of some group of individuals (the population) by studying only some of its members (the sample). • The survey you took today is a sample survey of the population at RBR. • Go To Gallup.com to see examples of sample surveys with real data. (found on page 7 in textbook)
Terms • Census-a sample survey that attempts to include the entire population in the sample. (Census.gov) • Experiment: purposely imposes some treatment on individuals in order to observe their responses. The purpose of an experiment is to study whether the treatment causes a change in the response. (found on pages 10-13 in textbook)
Example • Researchers want to know if listening to relaxing music for ten minutes immediately prior to a test improves students’ scores. They divide students into two groups, Group A and Group B. Both groups take the same exam, without listening to music before the exam. Both Group’s averages are the same. The following day the groups are given a new exam. Group A listens to relaxing music before their exams and Group B does not. The researchers conclude that Group A’s scores on the second exam were higher than Group B’s. • Was this study an experiment or an observational study? Explain. • Why did the researchers have the groups take the first test, both without listening to music. • What are some potential variables (or flaws) not covered in this study?
Exercise 2 In 2001, researchers announced that “children who spend most of their time in child care are three times as likely to exhibit behavioral problems in kindergarten as those who are cared for primarily by their mothers.” (a) Was this likely an observational study or an experiment? Why? (b) Can we conclude that child care causes behavior problems? Why or why not?
Assignments • Worksheet • Quiz Tues 9/19 (A-Day) or Wed 9/20 (B-Day) on Vocab Chapter 1
