Presentation on theme: "What is Statistics?. Art and Science of dealing with data. Data: numbers with a context (units)…makes it informative. Context engages our background."— Presentation transcript: 1 What is Statistics? Show
2 Art and Science of dealing with data. Data: numbers with a context (units)…makes it informative. Context engages our background knowledge and allows us to make judgments about the significance of the number. Uses data to gain insight and draw conclusions. 3 Sports Healthcare professionals. Public policy, and many different fields of study. Managers (efficient crunching of numbers results in a better bottom line). Scientists/Engineers This list could go on and on 4 1. Producing Data 2. Organizing and
Describing Data 3. Chance 4. Inference 5 Describes methods for producing data which can give clear answers to specific questions. Where the data comes from is important… Learn how to select samples and design. Experiments are very influential in statistics. Example –
Opinion polls, clinical trials, etc… 6 Methods and strategies for exploring, organizing and describing data. Using graphs and numerical summaries. Learn how to look at data intelligently. 7 Probability Variation Risk 8 Moves beyond the data to draw conclusions. Take into account that variation is everywhere Conclusions can be uncertain.
9 When we talk about data, a big part of stats is deciding what to measure in order to produce data that helps answer your questions. Need a clear objective before collecting data. Measurements are made on individuals and organized in variables. 10 What do these number mean to you? The birth weights of my kids The mean nothing without units 9.6 pounds and 9.0 pounds 11 Individuals – the objects described by a set of data Ex – people, animals, things Variable – any characteristic of an individual Can take different values for different individuals. Although Statistics deals with numbers. Not all variables are numerical. To use Statistics with other (non-numerical) variables we use counts or percents.
12 Quantitative variables – numerical values (you can perform any type of arithmetic with these) Ex – test
scores, age, salaries, etc… Categorical variables – use percents or counts; places an individual into one or several groups or categories Ex – grade level, class, eye color 13 14 Individuals
- ◦ Students in class Variables – 1. ID (categorical) 2. Grade Level (categorical, not numerical…Fresh, Soph, Junior, Senior OR 9, 10, 11, 12) 3. Gender (categorical) 4. HR (categorical) 5. Counselor (categorical) 6. Test 1 (numerical/quantitative) 15 1. Textbook: Pgs. 7&8 #1-4 2.
Data collection sheet 3. Celtics examples Presentation on theme: "Statistics The science of collecting, analyzing, and interpreting data. The Statistical Problem Solving Process: 1.Ask a question of interest 2.Produce."— Presentation transcript: 1 Statistics The science of collecting, analyzing, and interpreting data. The Statistical
Problem Solving Process: 1.Ask a question of interest 2.Produce or collect some data 3.Analyze, graph and describe the data 4.Make a conclusion, answering the question of interest 2 Individuals & Variables Individuals are the objects described by a set of data. –People, animals, or things
A Variable is any characteristic of an individual. Variables can take different values for different individuals. –Categorical Variables: places an individual into one of several categories (Job type, gender, race) –Quantitative Variables: takes numerical values for which ordering and averaging make sense (age, weight, salary)
3 Example: a few lines from a teacher's gradebook Name Gender Grade level Calc No. Test 1 Hsu, Danny M 12 B319 81 Iris, Francine F 12 B298 92 Ruiz, Ricardo M 11 B304 87 What individuals does this data describe? What variables does this data describe? –Which of these are categorical? –Which are quantitative?
Danny, Francine, and Ricardo Gender, grade level, calc no, and test grade Gender, calc no Grade level, test grade
4 Populations & Samples The population of interest in a statistical study is the entire group of individuals
about which we want information –A parameter is a number that describes the population A sample is a part of the population from which we actually collect information. –A statistic is a number that describes the sample Sample data is used to draw conclusions about the population as a whole. –A statistic helps to estimate a parameter
5 Example: TV ratings http://www.nielsen.com/us/en/nielsen-solutions/nielsen-measurement/nielsen-tv- measurement.html http://www.nielsen.com/us/en/nielsen-solutions/nielsen-measurement/nielsen-tv- measurement.html Market research is designed to
discover what consumers want and what products they use. One example of product research is the television rating service of Nielsen Media Research. The Nielsen ratings influence how much advertisers will pay to sponsor a program and whether or not the program stays on the air. Based on a 2010 study from 11,000 household people meters, Nielsen found that the average household has 2.5 TV's, 31% of the households own 4 or more TVs, and the average American watches 35.6 hours of TV a week. For this
study: –What is the population? –What is the sample? –What are the individuals? –What variables were measured? (C or Q?) –Are the numbers given (2.5, 31%, and 35.6) parameters or statistics? American households 11,000 households Each household # of TVs (Q/C), hrs watched (Q) statistics
6 Census http://www.census.gov/multimedia/www/videos/stats_in_action.php?intcmp=sldr4 http://www.census.gov/multimedia/www/videos/stats_in_action.php?intcmp=sldr4 A study that attempts to include the entire population in the sample. Censuses are often too costly and timely to conduct
so we take samples instead. The Bureau of Labor and Statistics and Census Bureau conduct a census of the US every 10 years and sample surveys much more frequently. –The Current Population Survey (CPS) interviews about 60,000 monthly. –The American Community Survey (ACS) interviews about 3,000,000 households each year. –http://www.census.gov/people/laborforce/publications/ACS-CPS_Comparison_Report.pdfhttp://www.census.gov/people/laborforce/publications/ACS-CPS_Comparison_Report.pdf
7 2 Types of Studies Observational Study Experimental Study 8
Observational Study An observational study observes individuals and measures variable(s) of interest but does not attempt to influence the responses. The purpose of an observational study is to describe some group or situation. 9 Experiments An
experiment deliberately imposes treatments 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. 10 The Beauty of Well Designed Experiments Everyone randomly chooses a red or blue
chip out of a bag. The red group is assigned to do jumping jacks for two minutes and the blue group is assigned to meditate for two minutes. After the two minutes, their heart rate is measured. Does the treatment cause the difference in heart rate? Since well designed experiments have an element of control, they can be used to imply causation (cause/effect) between the variables. 11 12 Observational Study or Experiment? A business is studying the relationship between physical fitness and productivity. They divide the employee volunteers into two groups (low and high fitness) and then compare their productivity once the fitness program has been completed. You want to determine what the most popular cars
on campus are. To do this, you go to the parking lot and record the types of cars for several samples from different areas of the lot. A insurance company wants to research if there is a difference in the number of children elementary and secondary teachers have. They submit a questionnaire to a random sample of teachers asking them to categorize themselves as elementary or secondary and how many children they have.
13 The Statistical Problem Solving Process - APAC A – Ask a question of interest P – Produce data A – Analyze and describe/graph the data C – Conclusion, answering the question
14 Using APAC http://www.usatoday.com/ http://www.usatoday.com/ Which element of APAC is shown here? What is a reasonable question of interest? How do you think the data were produced? –Observational or experimental? –What are the individuals? –What is the variable? –Is it quantitative or categorical? What can be concluded?
15 Additional example According to the National Institute on Media and the Family, a preschooler’s risk of obesity jumps 6% for every hour of television watched per day. The risk increases by 31% if the TV is in their
bedroom. –1.What element of APAC is given here? –2. What is a reasonable question of interest in this case? –3. The actual study that produced these results involved 2761 low- income adults in New York with children aged 1 to 4 years. Who are the individuals in this study? Do you think this was done with an observational study or an experimental study? –4. What variable(s) were measured? What is the science of collecting and analyzing data?Statistics is the practice or science of collecting and analyzing numerical data in large quantities, especially for the purpose of inferring proportions in a whole population from those in a representative sample.
What is an art and science that deals with the collection Organization creative presentation and analysis of data?Descriptive statistics deals with the presentation and collection of data. This is usually the first part of a statistical analysis.
Is statistics science or art?Answer: Statistics is both science and art. Statistical methods are systematic and have a general application which makes it a science. Further, the successful application of these methods requires skills and experience of using the statistical tools. These aspects make it an art.
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What is the art and science of collecting presenting analyzing and interpreting data?
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