The researcher was concerned about whether each maid’s BMI changed over the four-week study. Here are the results of a test performed using technology:

Mean of Paired Differences=0.2068t-Statistic=3.853 w/72 dfP=0.0003

Using the proper notation, how would you write the null hypothesis tested?

a. H₀: y¯Beginning=y¯End

b. H₀: y¯Beginning−y¯End=0

c. H₀: d¯Beginning−End=0

d. H₀: μBeginning−μEnd=0

e. H₀: μ_d=0