Chapter 2

Question 1

frequency (f)

Answer 1

• number of times a score occurs.

Question 2

distribution

Answer 2

• how something is arranged/displayed.

Question 3

frequency distribution

Answer 3

• an organized display.
• organizes data into a visual format.
• to see the spread of responses at a glance.
• descriptive statistic.

Question 4

frequency distribution tables

Answer 4

• categories in columns (highest to lowest).
• frequency count next to each category.
• x=variable, f=frequency, N=number of scores.
• summation of f=N

Question 5

calculating summation of x

Answer 5

• you can add up every score (ex: 2, 2, 4, 5, 5, 5, 7).
• create an fx column.

Question 6

relative frequencies

Answer 6

• describe each frequency in relation to total number.
• f/N=p (proportion)
• f/N(100)=percentage
• summation of p=1

Question 7

grouped frequency distribution tables

Answer 7

• used when there’s too many categories.
• information gets lost; individual scores can’t be retrieved.
• the wider the interval, the more information is lost.

Question 8

requirements of grouped frequency tables

Answer 8

• all intervals same width.
• lower score in each interval a multiple of the interval width.
• want 10 or fewer intervals.
• “simple” number for interval width (ex: 2, 5, 10).

Question 9

discrete

Answer 9

• exact scores.
• individuals with same recorded score had same measurements.

Question 10

continuous

Answer 10

• recorded values are rounded.
• individuals with same recorded score probably differed slightly.
• scores can be any value within the score’s real limits.

Question 11

real limits

Answer 11

• 1/2 unit above and below.

Question 12

apparent limits

Answer 12

• 1 unit smaller than real limits of the interval.

Question 13

frequency distribution graphs

Answer 13

• pictures of the data organized in tables.
• axes make up the boundaries.

Question 14

x-axis

Answer 14

• abscissa (measurement scale).

Question 15

y-axis

Answer 15

• ordinate (frequencies).

Question 16

histograms

Answer 16

• continuous data.
• interval and ratio scales (numerical).
• represent all scores on x-axis, even if frequency is zero.
• bars above each score (interval).
• height of bar corresponds to frequencies.

Question 17

modified histograms

Answer 17

• standard histograms can be made into “block” histograms.
• each block represents one per case.
• show the frequency count in each bar.

Question 18

polygons

Answer 18

• continuous data.
• interval and ratio scales (numerical).
• all numerical scores on x-axis, including f=0.
• dot above center of each interval.
• height of dot=frequency; connect dots with line; close polygon with lines to the y=0 point.

Question 19

bar graphs

Answer 19

• discrete data.
• non-numerical scores (nominal and ordinal scales).
• similar to histograms.
• spaces between adjacent bars indicate discrete categories (without a particular order=nominal, non-measurable width=ordinal).

Question 20

all graphs should have…

Answer 20

• x-axis and y-axis.
• appropriate labels for axes.
• even intervals on x and y.

Question 21

population distribution graphs: when population is small…

Answer 21

• scores for each member are used to make a histogram.
• absolute frequency is used.

Question 22

population distribution graphs: when population is large…

Answer 22

• scores for each member aren’t possible.
• relative frequency is used.

Question 23

relative frequency

Answer 23

• compares frequency of a category to a different category.

Question 24

normal curve

Answer 24

• symmetric with greatest frequency in the middle.
• common structure in data for many variables.

Question 25

frequency distribution shape

Answer 25

- symmetrical distribution. - skewed distribution.

Question 26

tail on the right

Answer 26

- positive skew.

Question 27

tail on the left

Answer 27

- negative skew.