TABLE 12-12
Recent Studies Have Found That American Children Are

TABLE 12-12
Recent studies have found that American children are more obese than in the past. The amount of time children spent watching television has received much of the blame. A survey of 100 ten-year-olds revealed the following with regards to weights and average number of hours a day spent watching television. We are interested in testing whether the average number of hours spent watching TV and weights are independent at 1% level of significance.
$\begin{array}{l|ccc|r} &{\text { TV Hours }} & \\\text { Weights } & 0-3 & 3-6 & 6+ & \text { Total } \\\hline \text { More than 10 lbs. Overweight } & 1 & 9 & 20 & 30 \\\text { Within 10 lbs. of normal weight } & 20 & 15 & 15 & 50 \\\text { More than 10 lbs. underweight } & 10 & 5 & 5 & 20 \\\hline \text { Total } & 31 & 29 & 40 & 100\end{array}$

-Referring to Table 12-12, the degrees of freedom of the test statistic are

A) 2.
B) 4.
C) 1.
D) 9.