1. Statistics Section 1.3 Mr. zboril | Milford PEP
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2. Chapter 1 Section 1.3 Introductions to Experimental Design
I am happy you are in my class. You are important to me – don’t ever think otherwise!
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3. Section 1.3 Focus Points Focus Points
Discuss what it means to take a census.
Describe simulations, observational studies, and experiments.
Identify control groups, placebo effects, completely randomized experiments, and randomized block experiments.
Discuss potential pitfalls that might make your data unreliable.

4. Section 1.3 Planning a Statistical Study
Guidelines for Planning a Statistical Study
Identify the individuals or objects of interest.
Specify the variables as well as the protocols for taking measurements or making observations.
Determine if you will use an entire population or representative sample. If using a sample, decide on a viable sampling method.
Issue ethics for collecting data. Request permission if necessary.
(cont’d on next slide)

5. Section 1.3 Planning a Statistical Study
Guidelines for Planning a Statistical Study (cont’d)
Collect the data.
Use appropriate descriptive statistics (Ch. 2, 3, 9) and make decisions using inferential statistics methods. (Ch )
Finally, note any concerns you might have about your data collection methods and list any recommendations for future studies.

6. Section 1.3 Experiments and Observations
In a census, measurement and observations from the entire population are used. Every 10 years, the US Department of Commerce conducts a census of the nation. This study asks numerous questions about your household and household members. By law, you are only required to provide the number of people who reside in your household. If data from only part of the population is used, the study is called a sample.

7. Section 1.3 Experiments and Observations
Differences between an observation study and experiment An observational study conducts observations and measurements of individuals in a way that doesn’t change the response of variable being measured. (example: does a group of students prefer Coke or Pepsi?) An experiment imposes a treatment on the individuals in order to observe a possible change in the response or variable being measured. (example: response of patients to a new medication.) Science Fair Grade School

8. Section 1.3 Example 4 Cook, Goats, and Flowers
Captain John Hook visited the Hawaiian Islands in 1778 and presented the islanders with several goats. The goats multiplied and were eating everything, including the silver sword plant. Biologists believed the goats were partially responsible for the decline in silver sword plant population. They conducted a study to verify their theory.

9. Section 1.3 Example 4 Cook, Goats, and Flowers
National Park biologists set up two plots of land - similar in climate, soil conditions, and plant population. The difference was only one of the plots was fenced to prevent access by goats. The plant population of both plots were counted. This study would be considered an experiment since a treatment (the fence) was imposed on one plot. The non-fenced plot is the control plot since no treatment was used, but the plot was similar in every other way.

10. Section 1.3 Example 4 Cook, Goats, and Flowers
The result of this study left little doubt….
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11. Section 1.3 Example 4 Cook, Goats, and Flowers
Captain Cook Monument in Hawaii…..

12. Section 1.3 Placebo Effect
The placebo effect occurs when a subject receives no treatment, but (incorrectly) believes he or she is receiving treatment and responds favorably.
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13. Section 1.3 Placebo Effect
In a medical study, often the patients are divided into two groups. One group receives treatment. The other group – the control group - receives the placebo. Following the treatment cycle, the medical condition of the control group (placebo) patients are compared with the treatment group. Our Statistics adventure continues with drilling into your heart and Example 5 on page 23…

14. Section 1.3 Example 5 Pg. 23 ‘Hole-Hearted’
block – a group of individuals sharing some common features that might affect the treatment.
randomized block experiment – individuals are first sorted into blocks, and then a random process is used to assign each individual in the block to one of the treatments.
The chart on page 24 is a randomized block design using gender for the blocks.
control group – receives the placebo or dummy treatment
Experiments like these are often double-blinded, meaning neither the individuals in the study or the observers know which subjects are receiving the treatment.

15. Section 1.3 Guided Exercise 5 Pg. 24
Which technique for gathering data – sampling, experiment, simulation, or census - would work best for the following studies?
Study the effect of stopping the cooling process of a nuclear reactor
SIMULATION
Study the amount of time college students with a full course load spend watching TV
SAMPLING AND USING AN OBSERVATION STUDY
Study of the effect on bone mass of a calcium supplement given to young girls.
EXPERIMENTATION WITH A CONTROL GROUP (PLACEBO) AND A TREATMENT GROUP
Study of the credit hour load of each student enrolled at the end of the drop/add period of this semester.
CENSUS

16. Section 1.3 Surveys Asking questions is the essence of surveying.
Questions where the answers range from strongly disagree to strongly agree – Likert Scale.
Survey Problems
Nonresponse
Truthfulness
Hidden Bias
Vague wording
Interviewer Influence
Voluntary Response

17. Section 1.3 Lurking and Confounded Variables
A lurking variable is one for which no data have been collected but that nevertheless has influence on other variables in the study. Example – A study involves two variables: 1) amount of gasoline used to commute to work and 2) length of time to commute. A lurking variable that would affect the study would be the level of traffic congestion. Two variables are confounded when the effects of one cannot be distinguished from the effects of the other. Example – A study involving grade point averages, course difficulty, study time, and IQ would be confounded as a student with a high IQ might have less available study time and opts for easier courses one semester.

18. I can stay afterwards for extra help
Mr. Zboril Contact Information
cell:
Class Time
1pm Tues & Thurs
I can stay afterwards for extra help

19. Statistics Chapter 1 Review
Mr. zboril | Milford PEP
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22. Ch. 1 Review Section 1.1 Variables
Is age a value? Yes – it is a quantitative variable. Is gender a value? No – it is a qualitative variable. Other quantitative variables would be height and weight. Other qualitative variables would be nationality, race, or religion.

23. Ch. 1 Review Section 1.1 Levels of Measurement
Nominal Level – names, labels or categories Ordinal Level – data that can be arranged in order Interval Level – data that can be arranged in order with meaningful differences Ratio Level – ratio of data also meaningful. Data has a true zero.

24. Chapter 1 Review - 1.2 Random-Number Table
Start anywhere on the table – the book starts at row 15, block 5, and lists the remaining numbers for that row The highest number assigned is 500. Since this has 3 digits, regroup the numbers into groups of three

25. Section 1.2 Other Sampling Techniques
Stratified Sampling : divide population into subgroups (called “strata”) based on specific characteristics such as age, income, etc. Draw random samples from each stratum.

26. Section 1.2 Other Sampling Techniques
Systematic Sampling : Number all members of the population sequentially. Then, from a starting point selected at random, include every kth member of the population in the sample.
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27. Section 1.2 Other Sampling Techniques
Cluster Sampling : Divide the entire population into pre-existing segments or clusters. Make a random selection of clusters and include every member of the cluster.
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28. Ch. 1 Review 1.3 Experiments and Observations
Differences between an observation study and experiment An observational study conducts observations and measurements of individuals in a way that doesn’t change the response of variable being measured. (example: does a group of students prefer Coke or Pepsi?) An experiment imposes a treatment on the individuals in order to observe a possible change in the response or variable being measured. (example: response of patients to a new medication.)

29. Ch. 1 Review - Section 1.3 Surveys
Asking questions is the essence of surveying.
Questions where the answers range from strongly disagree to strongly agree – Likert Scale.
Survey Problems
Nonresponse
Truthfulness
Hidden Bias
Vague wording
Interviewer Influence
Voluntary Response

30. Ch. 1 Review - Section 1.3 Question
A local news reporter is asking people on the street, “Do you think the governor’s mean-spirited budget, which slashes funding to state assistance programs for children and the elderly, is fair?” What is being done, here? Which survey pitfall is being described?

31. Ch. 1 Review Difference between statistic and parameter.
Control group and treatment group
That is all for Chapter 1.
Chapter 2 we get into graphing – this leads to my next question…
Who here can bring in a laptop that has Microsoft Excel?
Finally….the remnants of Harvey will pass through late tonight through Friday night. We may see

32. Ch. 1 Review
Finally….the remnants of Harvey will pass through late tonight through Friday night. We may see a few inches of rain. Be careful driving.