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Quiz 3

A regression equation models the relationship between hours studied and test scores as: TestScore = 65 + 2.5(HoursStudied) + ε. Which of the following would indicate a source of bias in the estimated effect of hours studied on test scores? (Select all that apply)

Students whose last name ended in the letter “S” were accidentally given 2 more points in the test
Students who study more also have access to better tutoring programs
Random noise in test-taking conditions
Students who study more hours tend to be more motivated in general

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Which of the following is an assumption necessary for a simple mean comparison to recover the causal effect?

The mean of the treatment group must equal the mean of the control group
The outcomes of the control group would be the same as the outcomes of the treatment group, had they received the treatment
Same sizes need to be the same between treatment and control
The difference in means should be economically significant

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Imagine we have the following model: Hospitalized=α + βVaccinated + ϵ. In this situation, what would Corr(Vaccinated, ε)≠0 imply?

The effect of vaccination on outcomes is causal
Vaccination is correlated with other factors affecting COVID-19 hospitalization rates
The mean of the error term is non-zero
That the variable vaccinations is a constant

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There is a promising new white noise machine that has been shown to help increase the hours people sleep. The developers of this product want to grow sales, but an investor is concerned that people who bought this machine may also be more likely to use other sleep aids, like melatonin, also influencing their amount of sleep. Which of the following regressions would allow the concerned investor to understand if the machine is making a difference? The following multiple-choice options contain math elements, so you may need to read them in your screen reader's “reading” or “browse” mode instead of “forms” or “focus” mode.

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