Systolic blood pressure of randomly selected HMO patients was recorded on a particular Wednesday, with the results shown here. An ANOVA test was performed using these data. $$\begin{array}{l}
\text { Patient Age Group }\
\begin{array} { | c | c | c | c | }
\hline \text { Under } 20 & 20 \text { to } 29 & 30 \text { to } 49 & 50 \text { and Over } \
\hline 105 & 110 & 122 & 139 \
113 & 101 & 114 & 115 \
108 & 112 & 128 & 136 \
114 & 127 & 124 & 124 \
123 & 123 & 125 & 123 \
\hline
\end{array}
\end{array}$$ Degrees of freedom for the between-treatments sum of squares would be:
A)3.
B)19.
C)17.
D)depends on ?.

Question

Systolic blood pressure of randomly selected HMO patients was recorded on a particular Wednesday, with the results shown here. An ANOVA test was performed using these data. $$\begin{array}{l}
\text { Patient Age Group }\
\begin{array} { | c | c | c | c | } 
\hline \text { Under } 20 & 20 \text { to } 29 & 30 \text { to } 49 & 50 \text { and Over } \
\hline 105 & 110 & 122 & 139 \
113 & 101 & 114 & 115 \
108 & 112 & 128 & 136 \
114 & 127 & 124 & 124 \
123 & 123 & 125 & 123 \
\hline
\end{array}
\end{array}$$ Degrees of freedom for the between-treatments sum of squares would be:
A)3.
B)19.
C)17.
D)depends on ?.

Quizplus · Accepted Answer

The degrees of freedom for the between-treatments sum of squares in an ANOVA test is calculated as the number of groups minus one. Here, there are 4 age groups, so the degrees of freedom is $4 - 1 = 3$.

Systolic Blood Pressure of Randomly Selected HMO Patients Was Recorded