Question

1. The mean cholesterol level of 40 to 60 year-old women surveyed in a particular country was found to be 5 mmol/l with a standard deviation is 1 mmol/l. The random variable is

	the number of women in the survey
	the ages of the women surveyed
	the cholesterol level

2. Which of the following statements is correct regarding the standard normal distribution?

	It is also called the z distribution
	Any normal distribution can be converted to the standard normal distribution
	The mean is 0 and the standard deviation is 1.
	All of these answers are correct.

3. A survey of Canadians showed the mean number of hours spent volunteering at any activity was 11 hours per year with a standard deviation of 1.5 hours. If the number of hours spent volunteering is normally distributed, what is the probability that a randomly selected person will have spent more than 15 hours volunteering over a one-year period?

	0.9962
	0.4962
	0.0038
	0.5038

4.For a uniform continuous probability distribution, the probability of observing any single observation of the random variable is equal to 1/(b-a).

	True
	False

5.To compute the median of a continuous uniform probability distribution we sum the minimum and maximum observations and divide the sum by 2.

	True
	False

6.A normal distribution refers to any symmetric probability distribution, whether discrete or continuous.

	True
	False

7. The total area under the normal curve

	equals 0.5
	equals 1.0
	varies depending on the problem being solved
	cannot be determined without more information

Answer 1

Solution:

1. The mean cholesterol level of 40 to 60-year-old women surveyed in a particular country was found to be 5 mmol/l with a standard deviation is 1 mmol/l. The random variable is

Answer: The cholesterol level

2. Which of the following statements is correct regarding the standard normal distribution?

Answer: All of these answers are correct.

3. A survey of Canadians showed the mean number of hours spent volunteering at any activity was 11 hours per year with a standard deviation of 1.5 hours. If the number of hours spent volunteering is normally distributed, what is the probability that a randomly selected person will have spent more than 15 hours volunteering over a one-year period?

Answer: 0.0038

Explanation:

We have to find:

Using the standard normal table, we have:

4.For a uniform continuous probability distribution, the probability of observing any single observation of the random variable is equal to 1/(b-a)

Answer: False because the probability of single observation of the continuous random variable is always 0

5.To compute the median of a continuous uniform probability distribution we sum the minimum and maximum observations and divide the sum by 2.

Answer: TRUE because the median of the uniform distribution is:

6.A normal distribution refers to any symmetric probability distribution, whether discrete or continuous.

Answer: False because normal distribution is a continuous distribution.

7. The total area under the normal curve

Answer: equal to 1.0