chapter 2

Question 1

what is a database?

Answer 1

a collection of information

Question 2

what is data called that has 2 variables?

Answer 2

bivariate data

Question 3

what does a pictogram use?

Answer 3

symbols or pictures to represent a number of items

Question 4

in a bar chart…

Answer 4

• bars are equal widths with equal spaces between them
• the height (or length) of the bar represents the frequency

Question 5

what is a vertical line graph?

Answer 5

similar to a bar chart- has lines instead of bars

Question 6

what do multiple bar charts have?

Answer 6

more than one bar for each class

Question 7

in a composite bar chart what does each bar show?

Answer 7

how the total frequency for that category is made up from different component groups

Question 8

what does a stem & leaf diagram show?

Answer 8

numerical data- split into a “stem” and “leaves”

Question 9

how are the numbers written in a stem & leaf diagram?

Answer 9

in order

Question 10

what does the stem & leaf diagram show?

Answer 10

the shape of the data distribution

Question 11

what does a back to back stem & leaf diagram show?

Answer 11

two sets of data with the same stem

Question 12

on back to back stem & leaf diagram where are the smallest values on each row?

Answer 12

nearest to the stem

Question 13

a pie chart is a way to display data in what way?

Answer 13

when you want to show how something is shared/divided

Question 14

what does a pie chart use to represent frequency?

Answer 14

area

Question 15

what do the angles at the centre of the pie chart add up to?

Answer 15

360 degrees

Question 16

in a pie chart, what is the area of the sector proportional to?

Answer 16

proportional to the frequency of the category

Question 17

what is the area of the pie chart proportional to?

Answer 17

the total frequency

Question 18

if two sets of data have different frequencies and they were drawn the same size- why is this bad?

Answer 18

it is misleading

Question 19

what are areas in comparative pie charts like?

Answer 19

the area of the 2 pie charts are in the same ratio as the two frequencies

Question 20

what are comparative pie charts used for?

Answer 20

to compare 2 sets of data

Question 21

how to compare the total frequencies of comparative pie charts?

Answer 21

compare the areas

Question 22

how to compare the proportions of comparative pie charts?

Answer 22

compare the individual angles

Question 23

what are population pyramids similar to?

Answer 23

bar charts or stem and leaf diagrams

Question 24

what do population pyramids show?

Answer 24

the age groups in a population- usually divided by gender

Question 25

what is a choropleth map used for?

Answer 25

used to classify regions of a geographical areas

Question 26

in choropleth maps how are regions shaded?

Answer 26

with an increasing depth of colour

Question 27

why is a key required in choropleth maps?

Answer 27

to show what each shade represents

Question 28

a choropleth map can also be....

Answer 28

a diagram instead of a map

Question 29

what is a histogram similar to?

Answer 29

a bar chart

Question 30

what type of data do histograms use?

Answer 30

continuous data

Question 31

why are there no gaps between the bars in histograms?

Answer 31

because the data is continuous

Question 32

what does a frequency polygon do?

Answer 32

joins the mid-points of the top of the bars with straight lines

Question 33

what is cumulative frequency?

Answer 33

a running total of frequencies

Question 34

when would a cumulative frequency step polygon be used?

Answer 34

for discrete data

Question 35

when would a cumulative frequency diagram be used?

Answer 35

for grouped continuous data

Question 36

with a cumulative frequency diagram, how do you join the points?

Answer 36

with a smooth curve

Question 37

what can cumulative frequency diagrams be used for?

Answer 37

to estimate or predict other values

Question 38

what does a histogram show about the data?

Answer 38

how the data is distributed across the class intervals

Question 39

what direction will positive skew be in?

Answer 39

-> ( going right)

Question 40

what direction will negative skew be in?

Answer 40

<- (going left)

Question 41

what do you need to do when drawing a histogram with unequal class intervals?

Answer 41

need to adjust the height of the bars so that the area of the bar represents the frequency

Question 42

with histograms with equal class intervals, what represents the frequency?

Answer 42

the height

Question 42

in histograms with unequal class intervals what represents the frequency?

Answer 42

the area of the bar

Question 42

how to figure out frequency density?

Answer 42

frequency/class width

Question 43

when can you compare data in histograms?

Answer 43

- if they have the same class intervals - if they have the same frequency density scales

Question 44

what are some features of misleading diagrams?

Answer 44

- scales that do not start at zero - lines on a graph that are too thick to interpret information - graphs and charts without keys may be misleading

Question 45

why do 3D diagrams make comparisons difficult?

Answer 45

- things at the front of the diagram can appear larger than those at the back - sections from the diagram separated from other parts make comparisons difficult

Question 46

what do bar charts and line graphs show?

Answer 46

trends and patterns in data