Practice Questions from Chapter 1&2

Question 1

For the interval 1.75-1.99 (where scores are rounded to the nearest hundreth, the interval width is

Answer 1

0.25

Question 2

For the interval 1.75-1.99 the lower real limit is

Answer 2

1.745

Question 3

For the interval 1.75-1.99 and the upper real limit is

Answer 3

1.995

Question 4

For the interval 60-70, where scores are rounded to the nearest ten, the interval width is

Answer 4

11

Question 5

For the interval 60-70 the lower real limit is

Answer 5

55

Question 6

For the interval 60-70 and the upper real limit is

Answer 6

75

Question 7

A researcher collects information on the height of every single US president to look for a correlation between height and success as president. In this case, presidents would be

Answer 7

Population

Question 8

The purpose of descriptive statistics is to

Answer 8

organize and summarize observations so that they are easier to understand

Question 9

To say that a score of 120 is 20% higher than a score of 100, is appropriate for

Answer 9

Ratio scale

Question 10

You collected data from a sample of 100 teenagers on the number of minutes per day that they spend on social media. In order to depict your results graphically, your best option is to use

Answer 10

histogram

Question 11

Frequency distributions can be reported as

Answer 11

Raw frequencies, proportions, cumulative frequencies

Question 12

Relative frequency distributions can be useful when

Answer 12

you want to compare two samples that are of different sizes

Question 13

If a frequency distribution has class intervals of 54-57, 58-61 and 62-65, the interval width (i) is

Answer 13

4

Question 14

If a frequency distribution has class intervals of 54-57, 58-61 and 62-65, the real limits of that last class interval are

Answer 14

61.5-65.5

Question 15

If I want to describe the ethnicity of students in my classroom, the best measure of central tendency would be

Answer 15

The mode

Question 16

When computing the variance, why do we square every deviation score?

Answer 16

In order to keep the scores from summing up to 0

Question 17

When a distribution is very skewed, the most accurate measure of variability will be

Answer 17

Semi-interquartile range

Question 18

Imagine a distribution of six scores. What follows are the deviation scores for five of those scores (that is, how each score deviates from the mean): -7, -4, +1, +3, and +5. What is the deviation score of the last number?

Answer 18

+2 (since they must add up to zero)

Question 19

Converting a score in your distribution into z scores allows one to

Answer 19

determine the distance between that score and the mean of the distribution in a standard metric

Question 20

A positive skew may have a tail that indicates extreme scores ________ the center of the distribution.

Answer 20

Above

Question 21

A negative skew may have a tail that indicates extreme scores ________ the center of the distribution.

Answer 21

Below

Question 22

A grouped frequency table is most useful when….

Answer 22

Data vary over a large range of continuous values

Question 23

A ________ is a structured presentation of data based on frequencies of classes rather than frequencies of specific values.

Answer 23

Grouped frequency table