Question

A pediatrician randomly selected 50 six-month-old boys from her practice's database and recorded an average weight of 15.6 pounds with a standard deviation of 0.45 pounds. She also recorded an average length of 25.7 inches with a standard deviation of 0.27 inches.

(a) Find a 95% confidence interval for the average weight (in pounds) of all six-month-old boys. (Round your answers to two decimal places.)_____ lb to______ lb

(b) Find a 99% confidence interval for the average length (in inches) of all six-month-old boys. (Round your answers to two decimal places.) in ____ to ______in

(c) What do you have to assume about the pediatrician's database in order to make inferences about all six-month-old boys?

1. The pediatrician's database must contain all measurements from the entire population of six-month old boys.

2. The pediatrician's database must be updated daily.

3. The pediatrician's database must produce intervals that contain the respective sample means.

4. The pediatrician's database must be kept secure using state of the art security software.

5. The pediatrician's database must be representative of the entire population of six-month old boys.

Answer 1

(a)

(b)

(c) 5. The pediatrician's database must be representative of the entire population of six-month old boys.