Answer: To calculate the % confidence interval for the proportion of US adults who spend less than three hours watching TV on an average day, we can use the following formula:
p +/- z*(sqrt(p(1-p)/n))
Where:
p = proportion of US adults who spend less than three hours watching TV on an average day (0.42)
z = standard normal score for a given level of confidence (e.g. for a 95% confidence level, z = 1.96)
n = sample size (1031)
Plugging in the given values, we get:
0.42 +/- 1.96*(sqrt(0.42*(1-0.42)/1031))
Simplifying, we get:
0.42 +/- 0.0156
So the 95% confidence interval for the proportion of US adults who spend less than three hours watching TV on an average day is approximately (0.40,0.44)
So the answer is (0.40,0.44)
Explanation: