Question

1. If the standard deviations of x and y are 12.5 and 10.8, respectively, and the covariance is 118.8, then the coefficient of correlation r is 0.88.

True

False

2. Generally speaking, if two variables are unrelated (as one increases, the other shows no pattern), the covariance will be:

	a.	a large positive number.
	b.	a large negative number.
	c.	a positive or negative number close to zero.
	d.	None of these choices.

3. z is a standard normal random variable. The P (-1.20 z 1.50) equals

	a.	0.8181
	b.	0.3849
	c.	0.0483
	d.	0.4332

4. A normal probability distribution

	a.	is a continuous probability distribution.
	b.	must have a standard deviation of 1.
	c.	can be either continuous or discrete.
	d.	is a discrete probability distribution.

Answer 1