The CDC wants to determine why COVID-19 infection rates are lower in some states than in others. What statistical method would be most appropriate?

Group of answer choices

a. A confidence Interval with the expected number of infections per state as the mean

b. A regression with the infection rate as the independent variable

c. A hypothesis test with a null hypothesis that the infection rate is greater than or equal to the expected number

d. A regression with the infection rate as the dependent variable

e. A hypothesis test with a null hypothesis that the infection rate is less than or equal to the expected number