Question

The volume of soft drink in plastic bottles is a normal random variable with mean 16 ounces and a standard variable deviation 0.6 ounce.

1. For all possible random samples of 25 bottles, what is the shape of the sampling distribution of the sample means?
2. What is the likelihood that in a random sample of 25 bottles the mean volume is more than 14.5 ounces?
3. What is the probability that in a random sample of 25 bottles the mean volume is below 15.8 ounces?

The mean weight of 10 randomly newborn babies at a local hospital is 7.14 lbs and the standard deviation of 0.817 lbs. Assume the weight of newborn babies has     approximately normal distribution.

1. Find the margin of error for a confidence level of 90%.

2. Fill in the blanks in the following sentence.

       % of all samples of size            have sample means within               of the population mean.

3. Find the 90% confidence interval for the mean weight at this hospital.

Assume that the finishing times in a New York City 10-kilometer road race are normally distributed with a mean of 61 minutes and a standard deviation of 9 minutes. Let X be a randomly selected finishing time.

1. What is the probability that a that a person running a 10-kilometer road race in New York City, will end up with finishing times average between 52 and 70 minutes for a road race?
2. Find the value of the 95% percentile, P₉₅, for this random variable.
3. Use the information from part (b) to circle the correct choice and to fill in the blanks in the following sentence:

           % of finishing time average (at least/at most)                   minutes in a New York City 10-kilometer road race.

Answer 1

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b)

  

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Use Z- table or Excel function =NORMSDIST(z)