Chapter 6 Stats

+/- 1 sd away from mean

68.26%

+/- 2 sd away from mean

95.44%

+/- 3 sd away from mean

99.72%

z value with .10 in upper tail

=Norm.s.inv(.9)

z value with .025 in lower tail

=norm.s.inv(.025)

A standard normal distribution is a normal distribution with Select one: a. a mean of 1 and a standard deviation of 0 b. a mean of 0 and a standard deviation of 1 c. any mean and a standard deviation of 1 d. any mean and any standard deviation

A mean of 0 and a standard deviation of 1.

A continuous random variable may assume Select one: a. all values in an interval or collection of intervals b. only integer values in an interval or collection of intervals c. only fractional values in an interval or collection of intervals d. all the positive integer values in an interval

All values in an interval or collection of intervals.

The probability of the random variable assuming a value within some given interval from x1 to x2 is defined to be the

Area under the graph of the probability density function

can assume any value in an interval on the real line or in a collection of intervals.

Continuous random variable

Excel's NORM.INV function can be used to compute Select one: a. cumulative probabilities for a standard normal z value b. the standard normal z value given a cumulative probability c. cumulative probabilities for a normally distributed x value d. the normally distributed x value given a cumulative probability

The normally distributed x value given a cumulative probability.

Is the most important distribution for describing a continuous random variable.

normal probability distribution

smaller sd for a normal probability curve results in?

smaller curves

A random variable having a normal distribution with a mean of 0 and a standard deviation of 1 is said to have a

standard normal probability distribution.

The letter z is used to designate the

standard normal random variable

Excel's NORM.DIST function can be used to compute Select one: a. cumulative probabilities for a standard normal z value b. the standard normal z value given a cumulative probability c. cumulative probabilities for a normally distributed x value d. the normally distributed x value given a cumulative probability

Cumulative probabilities for a normally distributed x value.

A normal probability distribution Select one: a. is a continuous probability distribution b. is a discrete probability distribution c. can be either continuous or discrete d. always has a standard deviation of 1

Is a continuous probability distribution.

The highest point of the normal probability distribution curve is?

Mean, median, and mode

is used to compute the cumulative probability given an x value

Norm.Dist (value, mean, sd, true)

is used to compute the x value given a cumulative probability

Norm.Inv(probability, mean, sd,

is used to compute the cumulative probability given a z value.

Norm.S.Dist (z-score)

is used to compute the z value given a cumulative probability.

Norm.S.INV (probability)

Measure of the number of standard deviations x is from u.

Z-score

Larger sd for a normal probability curve results in?

wider, flatter curves

What is the skewness of a normal probability distribution

zero