How does random assignment help ensure the internal validity of our interpretation of the
data?
Question 2 (2 points)
There is a strong correlation between whether a mother smokes and the health of her children.
The children of mothers who smoke have more health problems than the children of mothers
who do not smoke. Do these data allow us to conclude that smoking causes poor health in
children?
Question 3 (2 points)
Here are some summary statistics for the ages of students in the undergraduate and graduate
programs at one Medical University.
Degree level Mean age Standard deviation
Undergraduate μ=22 years σ= 5 years
Graduate μ=38 years σ=12.5 years
Student GH is a 20-year-old undergraduate student and ME is a 33-year-old graduate student
at the university.
Relative to their degree level, which student is younger?
Question 4: (4 points)
A set of average city temperatures in December are normally distributed with a mean of 16.3°
Celsius and a standard deviation of 2°Celsius.
What proportion of temperatures are between 12.9 and C14.9?