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Statistics and probability

Course: Statistics and probability>Unit 6

Lesson 4: Types of studies (experimental vs. observational)

Worked example identifying experiment

Worked example identifying experiment.

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• In a well-designed study, wouldn't it be the case that the doctors would also be unaware who got the real pill and who received the placebo - a double blind study?
• This was an example of a poorly-executed study. The fact that the groups were told what groups got what would create bias.
• I wonder if instead of telling neither group what they are taking, telling both groups that they are taking the real pill would be even better since it would probably increase a placebo effect?
• Whenever you have a pill, it is probably assumed by you that it is a real pill and not a placebo one. So I guess when they say they wouldn't tell either group if the pill is real or not, they mean that for patients it is the real pill.
• A question stated:

The mayor of Statville has to decide how to allocate her education budget between the two high schools in town, “Stat Sticks” and “Datum High.” To decide which school deserves a bigger portion of the budget, she went over the grade sheets of the students from both schools in the past 5 years, and analyzed the data. She found that the overall grade average of “Stat Sticks” students is 4 points higher than the overall grade average of the students of “Datum High.”

And the answer to "what valid conclusion can be made from the result?" was

Students from “Stat Sticks,” in the last 5 years, had higher grades, on average, than students from “Datum High.”

But there was another option that specified the overall grade for each student being 4 points higher, I was wondering why that one was incorrect and the one more generally saying it was higher was correct.