Chapter 2

Question 1

The pth percentile of a distribution is the value with p percent of the observations less than it

Answer 1

Percentile

Question 2

We plot a point corresponding to the cumulative relative frequency in each class at the smallest value of the next class.

Answer 2

Cumulative Relative Frequency Graph

Question 3

If x is an observation from a distribution that has known mean and standard deviation, the standardization score for x is

Z= (x-mean)/(standard deviation)

A standardization score is often called a z-score.

Answer 3

Standardized Score (z-score)

Question 4

Is a curve that

• is always on or above the horizontal axis, and
• has area exactly 1 underneath it

It describes the overall pattern of a distribution. The area under the curve and above any interval of value on the horizontal axis is the proportion of all observations that fall in that interval

Answer 4

Density curve

Question 5

Is the pint at which the curve would balance if made of solid material.

Answer 5

Mean of a density curve

Question 6

Is the equal-areas point, the point that divides the area under the curve in half

Answer 6

Median of a density curve

Question 7

Is the balance point at which the curve would balance if made of solid material.

Answer 7

Mean of a density curve

Question 8

Is described by a normal density curve. Any particular normal distribution is completely specified by two numbers: it’s mean “u” and standard deviation ó

Answer 8

Normal distribution

Question 9

The mean of a normal distribution is at the center of the symmetric ———–

Answer 9

Normal Curve

Question 10

Is the normal distribution with mean 0 and standard deviation 1

Answer 10

Standard normal distribution

Question 11

Table A is a table of areas under the standard normal curve. The table entry for each value z is the area under the curve to the left of z.

Answer 11

The standard normal table