Chapter 3

Question 1

Stem-and-leaf plots

Answer 1

presents quantitative data in a graphical format, similar to a histogram, to assist in visualizing the shape of a distribution.

Question 2

Quartiles

Answer 2

Are the values that divide a list of numbers into quarters.

Question 3

Box-and-whiskers plots

Answer 3

a way to show the spread and centers of a dataset.

Question 4

Frequency histograms

Answer 4

a special graph that uses vertical columns to show frequencies (how many times each score occurs).

Question 5

Kurtosis

Answer 5

measure of whether the data are heavy tailed or light tailed relative to a normal distribution.

Question 6

Mesokurtic

Answer 6

distribution defined as kurtosis=0 normal distribution.

Question 7

Leptokurtic

Answer 7

a distribution having excess positive kurtosis greater than 3. The tails are fatter than in normal distribution.

Question 8

Platykurtic

Answer 8

distribution has a negative kurtosis. The tails are very thin and equates to a uniform distribution.

Question 9

Skewness

Answer 9

measure of symmetry, or more precisely, the lack of symmetry.

Question 10

Positive skewness

Answer 10

Right tail is longer and the mass is concentrated to the left.

Question 11

Negative skewness

Answer 11

Left tail is longer and the mass is concentrated on the right.

Question 12

None skewness

Answer 12

close to 0 skewness, does not imply that the mean= median.