Chapter 1 Section 1 Introduction to the Practice

Chapter 1 Section 1 Introduction to the Practice of Statistics Sullivan – Statistics: Informed Decisions Using Data – 2 nd Edition – Chapter 1 Section 1 – Slide 1 of 20

Chapter 1 – Section 1 ● Learning objectives 1 § Define statistics and statistical thinking 2 § Understand the process of statistics 3 § Distinguish between qualitative and quantitative variables 4 § Distinguish between discrete and continuous variables Sullivan – Statistics: Informed Decisions Using Data – 2 nd Edition – Chapter 1 Section 1 – Slide 2 of 20

Chapter 1 – Section 1 ● Learning objectives 1 § Define statistics and statistical thinking 2 § Understand the process of statistics 3 § Distinguish between qualitative and quantitative variables 4 § Distinguish between discrete and continuous variables Sullivan – Statistics: Informed Decisions Using Data – 2 nd Edition – Chapter 1 Section 1 – Slide 3 of 20

Chapter 1 – Section 1 ● The science of statistics is § § Collecting Organizing Summarizing Analyzing information to draw conclusions or answer questions Sullivan – Statistics: Informed Decisions Using Data – 2 nd Edition – Chapter 1 Section 1 – Slide 4 of 20

Chapter 1 – Section 1 ● Anecdotal claims, as opposed to statistics, are § Conclusions based on very little data § Stories and rumors ● Data can be misused when § Data is incorrectly obtained § Data is incorrectly analyzed ● Good statistics should § Understand the difference between direct and indirect (lurking variable) relations § Understand the impacts of variability Sullivan – Statistics: Informed Decisions Using Data – 2 nd Edition – Chapter 1 Section 1 – Slide 5 of 20

Chapter 1 – Section 1 ● Statistics and mathematics have similarities but are different ● Mathematics § Solves problems with 100% certainty § Has only one correct answer ● Statistics, because of variability § Does not solve problems with 100% certainty (95% certainty is much more common) § Frequently has multiple reasonable answers Sullivan – Statistics: Informed Decisions Using Data – 2 nd Edition – Chapter 1 Section 1 – Slide 6 of 20

Chapter 1 – Section 1 ● Learning objectives 1 § Define statistics and statistical thinking 2 § Understand the process of statistics 3 § Distinguish between qualitative and quantitative variables 4 § Distinguish between discrete and continuous variables Sullivan – Statistics: Informed Decisions Using Data – 2 nd Edition – Chapter 1 Section 1 – Slide 7 of 20

Chapter 1 – Section 1 ● A population § Is the group to be studied § Includes all of the individuals in the group ● A sample § Is a subset of the population § Is often used in analyses because getting access to the entire population is impractical Sullivan – Statistics: Informed Decisions Using Data – 2 nd Edition – Chapter 1 Section 1 – Slide 8 of 20

Chapter 1 – Section 1 ● Identify the research objective § What questions are to be answered? § What group should be studied? ● Collect the information needed § Can you access the entire population? § How can you collect a good sample? § What other methods are available and appropriate? Sullivan – Statistics: Informed Decisions Using Data – 2 nd Edition – Chapter 1 Section 1 – Slide 9 of 20

Chapter 1 – Section 1 ● Organize and summarize the information § Descriptive statistics (chapters 2 through 4) § Visual methods such as charts and graphs § Numeric methods such as calculations ● Draw conclusions from the information § Inferential statistics (chapters 8 through 15) § Various methods that are appropriate for different questions and different types of data sets Sullivan – Statistics: Informed Decisions Using Data – 2 nd Edition – Chapter 1 Section 1 – Slide 10 of 20

Chapter 1 – Section 1 ● An example of a statistical study ● State the research objective – determine the effectiveness of a antihypertensive drug ● Collect the information – divide 1, 317 patients into two groups with two different treatments ● Organize the information – measure blood pressure data ● Draw the conclusions – extend the study results to conclusions about the entire population Sullivan – Statistics: Informed Decisions Using Data – 2 nd Edition – Chapter 1 Section 1 – Slide 11 of 20

Chapter 1 – Section 1 ● Learning objectives 1 § Define statistics and statistical thinking 2 § Understand the process of statistics 3 § Distinguish between qualitative and quantitative variables 4 § Distinguish between discrete and continuous variables Sullivan – Statistics: Informed Decisions Using Data – 2 nd Edition – Chapter 1 Section 1 – Slide 12 of 20

Chapter 1 – Section 1 ● Characteristics of the individuals under study are called variables § Some variables have values that are attributes or characteristics … those are called qualitative or categorical variables § Some variables have values that are numeric measurements … those are called quantitative variables ● The suggested approaches to analyzing problems vary by the type of variable Sullivan – Statistics: Informed Decisions Using Data – 2 nd Edition – Chapter 1 Section 1 – Slide 13 of 20

Chapter 1 – Section 1 ● Examples of qualitative variables § § § Gender Zip code Blood type States in the United States Brands of televisions ● Qualitative variables have category values … those values cannot be added, subtracted, etc. Sullivan – Statistics: Informed Decisions Using Data – 2 nd Edition – Chapter 1 Section 1 – Slide 14 of 20

Chapter 1 – Section 1 ● Examples of quantitative variables § § § Temperature Height and weight Sales of a product Number of children in a family Points achieved playing a video game ● Quantitative variables have numeric values … those values can be added, subtracted, etc. Sullivan – Statistics: Informed Decisions Using Data – 2 nd Edition – Chapter 1 Section 1 – Slide 15 of 20

Chapter 1 – Section 1 ● Learning objectives 1 § Define statistics and statistical thinking 2 § Understand the process of statistics 3 § Distinguish between qualitative and quantitative variables 4 § Distinguish between discrete and continuous variables Sullivan – Statistics: Informed Decisions Using Data – 2 nd Edition – Chapter 1 Section 1 – Slide 16 of 20

Chapter 1 – Section 1 ● Quantitative variables can be either discrete or continuous ● Discrete variables § Variables that have a finite or a countable number of possibilities § Frequently variables that are counts ● Continuous variables § Variables that have an infinite but not countable number of possibilities § Frequently variables that are measurements Sullivan – Statistics: Informed Decisions Using Data – 2 nd Edition – Chapter 1 Section 1 – Slide 17 of 20

Chapter 1 – Section 1 ● Examples of discrete variables § The number of heads obtained in 5 coin flips § The number of cars arriving at a Mc. Donald’s between 12: 00 and 1: 00 § The number of students in class § The number of points scored in a football game ● The possible values of qualitative variables can be listed Sullivan – Statistics: Informed Decisions Using Data – 2 nd Edition – Chapter 1 Section 1 – Slide 18 of 20

Chapter 1 – Section 1 ● Examples of continuous variables § The distance that a particular model car can drive on a full tank of gas § Heights of college students ● Sometimes the variable is discrete but has so many close values that it could be considered continuous § The number of DVDs rented per year at video stores § The number of ants in an ant colony Sullivan – Statistics: Informed Decisions Using Data – 2 nd Edition – Chapter 1 Section 1 – Slide 19 of 20

Summary: Chapter 1 – Section 1 ● The process of statistics is designed to collect and analyze data to reach conclusions ● Variables can be classified by their type of data § Qualitative or categorical variables § Discrete quantitative variables § Continuous quantitative variables Sullivan – Statistics: Informed Decisions Using Data – 2 nd Edition – Chapter 1 Section 1 – Slide 20 of 20