A gasoline distributor wonders whether an individual's income level influences the grade of gasoline purchased. The following is a contingency table from a random sample of 300 individuals: The null hypothesis is ___.
A) "income" is independent of "type of gasoline"
B) "income" influences "type of gasoline"
C) "income" is not independent of "type of gasoline"
D) "income" is related to "type of gasoline"
E) "regular" is independent of "premium"

Question

A gasoline distributor wonders whether an individual's income level influences the grade of gasoline purchased. The following is a contingency table from a random sample of 300 individuals:  The null hypothesis is ___.
A) "income" is independent of "type of gasoline" 
B) "income" influences "type of gasoline" 
C) "income" is not independent of "type of gasoline" 
D) "income" is related to "type of gasoline" 
E) "regular" is independent of "premium"

Quizplus · Accepted Answer

The null hypothesis is always that there is no relationship or no difference between the variables being studied. In this case, the null hypothesis is that income level and type of gasoline purchased are independent of each other.

A Gasoline Distributor Wonders Whether an Individual's Income Level Influences