1.1 - Statistics, Data and Graphs

Question 1

population

Answer 1

complete set of units that possess some common characteristics

Question 2

sample (2)

Answer 2

1. smaller but hopefully representative set of units from populations used to find true properties about that population
2. bigger sample size generally = better estimates

Question 3

variable

Answer 3

characteristic/ property measured on units (explain a response variable from one/more explanatory variables

Question 4

types of numerical (quantitative) data (2)

Answer 4

1. continuous
2. discrete

Question 5

types of categorical (qualitative) data (2)

Answer 5

1. ordinal
2. nominal

Question 6

continuous data

Answer 6

values within a range, can be measured (e.g. size)

Question 7

discrete data

Answer 7

fixed values, integer can be counted (e.g. number of chromosomes)

Question 8

ordinal data

Answer 8

n factor levels with implicit order (e.g. size class; small, medium, large)

Question 9

nominal data

Answer 9

n factor levels without implicit order (e.g. eye colour: blue, grey, green)

Question 10

categorical data graphics (2)

Answer 10

1. 1 variable:
   - pie chart
   - bar graph
2. 2/more variables:
   - grouped bar graph
   - stacked histogram

Question 11

numerical data graphics

Answer 11

1. 1 variable:
   - histogram (distribution of numerical variable)
   - bar graph
   - box-and-whisker plot
2. 2/more variables:
   - scatterplot

Question 12

graphics rules (3)

Answer 12

1. graphs need to have clear axes labels with units
2. graphs need to have clear figure legends
3. important to think about ranges of axes

Question 13

random sampling

Answer 13

each member of a population has an equal and independent chance of being selected

Question 14

sampling bias

Answer 14

systematic discrepancy between estimates and true population characteristics