Y ELLOW S TICKIE Q UESTIONS Chapter 1 (mostly) and a little from Chapter 2...

SampleStatistic (changes from sample to sample; can vary) PopulationParameter (is fixed; does not change) Examples include µ, p, σ S AMPLE VS. P OPULATION …

P OPULATION P ARAMETER VS. SAMPLE STATISTIC... The admissions director at a university has an idea. If IQ scores of the existing students at the university are high, the university can use this as a marketing tool. Administering IQ tests is expensive; but the university agrees to provide the admissions director with enough money to administer IQ tests to 50 students. So the director gives the IQ test to a random sample of 50 of the university’s 5,000 freshman. The mean IQ score for the sample of 50 freshmen is 112 with a standard deviation of 15.

P OPULATION PARAMETER VS. SAMPLE STATISTIC... The M&M Mars Company claims that in every bag of milk chocolate candies, there is 14% orange. So, we decide to see if they are really telling the truth. We purchase a large bag of regular milk chocolate M&M’s and count the total number of M&M’s; and of those (the total), how many/the number of orange M&M’s.

P OPULATION PARAMETER VS. SAMPLE STATISTIC... Y OUR TURN A recent poll (January 26, 2016) interviewed 1,007 Republican voters and asked if they would vote for Donald Trump. 41% said they would vote for Trump as President of the United States.

C ONFOUNDING VARIABLES... A confounding variable is a variable or factor that was not controlled for in a study, but can have an influence on the results of the study. Suppose you’re participating in a research study that looks at who catches colds. The researcher only records whether you got a cold after a certain period of time and your age (as the researcher believes that people of a certain age tend to get more colds). What other conditions could affect whether a person gets a cold or not?

C ONFOUNDING VARIABLES... Studies have shown that the more televisions per person in a given country, the longer the life expectancy in that country. Solution... Just send more televisions to countries who have a short life expectancy... ???... What are some possible confounding variables?

C ONFOUNDING VARIABLES... Y OUR TURN According to an ABC News article, “Teenagers who eat with their families at least five times a week are more likely to get better grades in school.” Suggest a variable(s) that may be confounded with whether families eat dinner together.

W ELL DESIGNED EXPERIMENTS... Random assignment: Use chance to assignment treatments. Double-blinding: neither the subjects nor the researchers know who got what treatment or who is in the control group. Placebo: A ‘fake’ treatment (i.e., a fake drug/pill) Control: Keep other variables that might affect the response the same for all groups. Replication: Use ‘enough’ in each group (treatment, control, placebo) so that any differences in the effects of the treatments can be distinguished from chance differences.

W ELL - DESIGNED EXPERIMENTS... Consider the following and comment on double- blinding, placebo, and replication. In 1997, the U.S. government financed an HIV study that examined dosage levels of AZT, a drug known at that time to cut the risk of HIV transmission from pregnant mothers to their babies by two-thirds. 12,000 women with HIV in Africa, Thailand, and the Dominican Republic participated. Researchers gave half sugar pills; neither the patient nor the health care professional administering the pills knew which were being given to individual patients.

W ELL - DESIGNED EXPERIMENTS... Consider the following and comment on double- blinding, placebo, and replication. Many utility companies have introduced programs to encourage energy conservation among their customers. An electric company placed small digital displays in 25 randomly selected households to show current electricity use and what the cost would be if this use continued for a month. Another 25 randomly chosen households were given a chart and information about monitoring their electricity use from their outside meter. A third randomly chosen 25 households received information about energy consumption but no help in monitoring electricity use.

W ELL - DESIGNED EXPERIMENT... Y OUR TURN Consider the following and comment on double- blinding, placebo, and replication. Fizz Laboratories has developed a new drug for relieving chronic pain. Sixty patients suffering from arthritis and needing pain relief are available to participate in the study. Twenty randomly-selected patients will receive the new drug; the next randomly chosen 20 patients will receive the existing drug; and the last 20 patients will receive a sugar pill. Neither the patients nor the health care providers will be aware of which treatment they are receiving.

N UMERIC ( QUANTITATIVE ) VARIABLES VS. CATEGORICAL ( QUALITATIVE ) VARIABLES... Each pair come up with five examples of each and write them down on your paper. Be prepared to share out. Five minutes.

M ARGINAL, JOINT, CONDITIONAL PROBABILITIES... Indiana Jones It’s a Small World Mr. Toad’s Wild Ride TOTALS Fudge Churro85720 Dole Whip TOTALS

M ARGINAL, JOINT, CONDITIONAL PROBABILITIES... Y OUR TURN NOW Screamn’Tower of Terror TrollyTOTALS Turkey Leg Corn Dog Ice Cream1236 TOTALS

S TATCRUNCH.... We will continue to practice... Anything specifically we want/need to practice so far?