Statistics Questions and Answers

Week 4 Quiz

Question 1:

Obtain the area under the standard normal curve to the right of . Round your answer to four decimal places.

Question 2:

Find the area under the standard normal curve to the left of . Round your answer to four decimal places.

Question 3:

Find the area under the standard normal curve to the left of . Round your answer to four decimal places.

Question 4:

Find the area under the standard normal curve between and . Round your answer to four decimal places.

Question 5:

Determine the following probability for the standard normal distribution. Round your answer to four decimal places.

Question 6:

Find the value for a normal distribution with and . Enter the exact answer.

Question 7:

Find the area between and under a normal distribution curve with and . Round your answer to four decimal places.

Question 8:

The delivery times for all food orders at a fast-food restaurant during the lunch hour are normally distributed with a mean of minutes and a standard deviation of minutes. Let be the mean delivery time for a random sample of orders at this restaurant. Calculate the mean and standard deviation of  .

Round your answers to two decimal places.

Mean of  minutes

Standard deviation of  minutes

Question 9:

Using the formulas for the mean and standard deviation of a discrete random variable, calculate to 2 decimal places the mean and standard deviation for the population probability distribution of the table below.

x	P(x)
69	0.20
79	0.23
81	0.39
98	0.18

μ =

σ =

Question 10:

A population has a distribution that is skewed to the left. Indicate whether the central limit theorem will apply to describe the sampling distribution of the sample mean of size.

The central limit theorem can be applied.

	The central limit theorem cannot be applied.
Question 11: The standard deviation of the 2014 gross sales of all corporations is known to be billion. Let be the mean of the 2014 gross sales of a sample of corporations. What sample size will produce the standard deviation of equal to billion? Assume.