A researcher is interested in determining whether typists are most productive in the morning, at midday, in the evening, or late at night. To answer this question, the researcher recruits 20 participants and assigns 5 participants to be measured at each time of day. To evaluate productivity, the researcher measures words typed per minute at each time of day.
Morning Midday Evening Night
99 42 80 82
80 32 83 78
99 45 94 79
98 49 70 97
79 38 79 96
Mean 91 41.2 81.2 86.4
SStotal = 9094.95
What are the degrees of freedom for the numerator of the F-ratio?
a. 2
b. 3
c. 16
d. 19