A nutritionist wants to determine how much time nationally people spend eating and drinking. Suppose for a random sample of 956 people age 15 or older, the mean amount of time spent eating or drinking per day is 1.78 hours with a standard deviation of 0.58 hour.
(a) A histogram of time spent eating and drinking each day is skewed right. Use this result to explain why a large sample size is needed to construct a confidence interval for the mean time spent eating and drinking each day.
(b) In 2010, there were over 200 million people nationally age 15 or older. Explain why this, along with the fact that the data were obtained using a rando sample, satisfies the requirements for constructing a confidnce interval.
(c) Determine and interpret a 90% confidence interval for the mean amount of time Americans spend eating and drinking each day.
(d) Could the interval be used to estimate the mean amount of time a 9 year old spends eating and drinking each day? Explain.