1 Birth weights in Finland are normally distributed with a m

1. Birth weights in Finland are normally distributed with a mean of 3750 g and a standard deviation of 500 g.

a. Suppose a hospital in Finland requires special treatment for newborn babies weighing less than 2800 g. What percentage of newborn babies require special treatment?

b. What is the probability that a baby born at this hospital will weigh more than 4990 g (or 11 pounds)?

c. If a mother is told that her baby’s weight is at the 60th percentile, what is the baby’s weight?

d. A researcher is concerned about a particular OB/GYN’s practices. She checks the birth weights of 27 babies born under this doctor’s care. What is the probability their mean weight is less than 3500 g?

2. Based on data from the National Health and Nutrition Examination Survey, assume that weights of men are normally distributed with a mean of 172 pounds and a standard deviation of 29 pounds. What is the probability that 20 randomly selected men have a mean weight greater than 180 pounds?

3. A polling organization takes a random sample of 500 people and finds that 175 think they pay too much for car insurance.

a. Construct a 99% confidence interval for the true proportion of people who think they pay too much for car insurance.

b. Based on your confidence interval, can you state that more than a third of people think they pay too much for car insurance?

4.Parking meters have served as a revenue stream for several large cities. A random sample of 75 parking meters yielded a mean of $120 per meter per day with a standard deviation of $30.

a. Construct a 90% confidence interval for the population mean revenue collected from all parking meters.

b. Based on your confidence interval, can you say that the mean daily revenue per meter is more than $115?

5. You work for a consumer advocate agency and want to find the mean repair cost of a washing machine. As part of your study, you randomly select 45 repair costs and find the mean to be $104.50. Assume the population standard deviation is $17.50.

a. Construct a 95% confidence interval for the population mean repair cost of a washing machine.

b. Based on your confidence interval, can you say the mean repair cost of a washing machine is greater than $100?

Please help me out!

Solution