TABLE 11-13
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 regard to weights and average number of hours a day spent watching television. We are interested in testing whether the mean number of hours spent watching TV and weights are independent at 1% level of significance.

-Referring to Table 11-13, the critical value of the test will be ________.
A) 6.635
B) 13.277
C) 14.860
D) 21.666

Question

TABLE 11-13
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 regard to weights and average number of hours a day spent watching television. We are interested in testing whether the mean number of hours spent watching TV and weights are independent at 1% level of significance.
 
-Referring to Table 11-13, the critical value of the test will be ________.
A) 6.635 
B) 13.277 
C) 14.860 
D) 21.666

Quizplus · Accepted Answer

Since we are testing whether the mean number of hours spent watching TV and weights are independent, we will use a chi-square goodness-of-fit test. From the table, we see that there are 4 categories (underweight, normal weight, overweight, and obese) for weights and the degrees of freedom will be 4-1=3. Using a 1% level of significance and 3 degrees of freedom, the critical value from the chi-square distribution table is 13.277, which corresponds to choice B.

TABLE 11-13 Recent Studies Have Found That American Children Are More Obese