Chapter 6

According to the Central Limit Theorem, if a distribution follows a bell-shaped, symmetrical curve centered around the mean, approximately 68, 95, and 99.7 percent of its values will fall within one, two, and three standard deviations above and below the mean respectively. A) True B) False

A) False

The z-score follows a normal distribution with μ = 1 and σ = 0, which is known as the standard normal distribution. A) True B) False

A) False

The area under the curve of the normal probability distribution is always equal to 1.0. A) True B) False

A) True

The left and right ends of the normal probability distribution extend indefinitely, never quite touching the horizontal axis. A) True B) False

A) True

The mathematical expression that describes the shape of normal curves is known as the normal probability density function. A) True B) False

A) True

The z-score in a normal probability distribution determines the number of standard deviations that a particular value, x, is from the mean. A) True B) False

A) True

A smaller standard deviation for the normal probability distribution results in A) a skinnier curve that is tighter and taller around the mean. B) a skinnier curve that is more spread out around the mean and not as tall. C) a fatter curve that is more spread out around the mean and not as tall. D) a fatter curve that is tighter and taller around the mean.

A) a skinnier curve that is tighter and taller around the mean.

A normal probability distribution's standard deviation completely describes its shape.

B) False

The ________ probability distribution is bell-shaped and symmetrical. A) Poisson B) normal C) exponential D) uniform

B) normal

Which of the following statements is true regarding z-scores for the normal probability distribution? A) z-scores are equal to 1.0 for values of x that are equal to the distribution mean. B) z-scores are positive for values of x that are less than the distribution mean. C) z-scores are zero for values of x that are less than the distribution mean. D) z-scores are negative for values of x that are less than the distribution mean.

D) z-scores are negative for values that are less than the distribution mean.