week 1: introduction to measurement (IA & IB)

Question 1

what are the two different types of variables?

Answer 1

• numeric
• categorical

Question 2

what is a numeric variable?

Answer 2

describes a measurable quantity

Question 3

what is a categorical variable?

Answer 3

sorted to categories based on qualitative description

Question 4

what are the types of numeric variables?

Answer 4

• continuous & discrete (UK)
• interval scale & ratio scale (US)

Question 5

what is a continuous numeric variable?

Answer 5

• a variable that can take any possible value within a given range
• (ex: temperature in Celsius)

Question 6

what is a discrete numeric variable?

Answer 6

• a variable that can take specific values within a given range
• there are gaps in the range of variables
• typical discrete variable is a count (of integers)
• (ex: number of teeth)

Question 7

define interval scale and ratio scale numeric variables

Answer 7

interval scale: a variable whose values are graded in equal increments (ex: temperature in Celsius, 0˚C doesn’t mean anything)

ratio scale: same as interval scale, however a true 0 exists, true absence of quantity (ex: temperature in Kelvin (0K exists))

Question 8

what are the types of categorical variables?

Answer 8

• normal categorical (nominal scale)
• ordered categorical (ordinal scale)
• binary

Question 9

what is a normal categorical variable?

Answer 9

• a variable that is divided into different categories not in any ordered way
• (ex: brand of car)
• also known as nominal scale

Question 10

what is an ordered categorical variable?

Answer 10

• a variable that is divided into different categories in an ordered manner
• (ex: income level categorized as “low, middle, high” income)
• also known as ordinal scale

Question 11

what is a binary categorical variable?

Answer 11

a variable with ONLY 2 categories
(ex: affected by disease [yes/no])

Question 12

what type of variables are each of these examples:
(1) blood triglyceride levels
(2) dietary pattern (very healthy, moderately healthy, moderately unhealthy, very unhealthy)
(3) cyprus districts (larnaca, limassol, nicosia, etc)
(4) number of asthma attacks per month

Answer 12

(1) continuous numeric
(2) ordered categorical (ordinal)
(3) normal categorical (nominal)
(4) discrete numeric

Question 13

more operations can be made with which type of variable?

Answer 13

numeric

Question 14

what is considered more informative when presented with categorical data?

Answer 14

proportions rather than actual (absolute) numbers

Question 15

what are the different ways you can present categorical data?

Answer 15

• frequency table (showing numbers and proportions
• bar graphs
• pie charts

Question 16

what does a bar graph display?

Answer 16

displays the distribution of a categorical variable, showing the counts for each category next to each other for easy comparison

Question 17

what does a pie chart display?

Answer 17

• displays the total population/sample as a circle
• the circle is sliced into pieces whose size is proportional to the fraction of the whole in each category

Question 18

what are the different ways we can present numeric data?

Answer 18

• measures of central tendency: a single, central, typical value for a given variable around which other cluster
• measures of dispersion: the extent of spread of values of a given variable (especially with respect to the central value of a distribution)

Question 19

what are the examples of measures of central tendency?

Answer 19

mean, median, mode

Question 20

what are the examples of the measures of dispersion?

Answer 20

variance, standard deviation, interquartile range