A researcher recorded the number of e-mails received in a month and the number of online purchases made during that month for 50 people with an online presence. The resulting data were used to conduct a hypothesis test to investigate whether the slope of the population regression line relating number of e-mails received to number of online purchases is positive. What are the correct hypotheses for the test?
a. H0:β1=0Ha:β1≠0
b. H0:β1=0Ha:β1>0
c. H0:β1=0Ha:β1<0
d. H0:β1>0Ha:β1=0
e. H0:b1=0Ha:b1≠0