Lecture 1

Question 1

Data

Answer 1

Data are the facts and figures collected, summarized, analyzed, and interpreted

Question 2

Dataset

Answer 2

The data collected in a particular study are referred to as the data set

Question 3

Elements

Answer 3

The elements are the entities on which data are collected.
Examples: individuals, firms, countries

Question 4

Variable

Answer 4

A variable is a characteristic of interest for the elements
Examples: shoe size, number of employees, GDP

Question 5

observation

Answer 5

The set of measurements collected for a particular element
Example: shoe size 44, 10 employees, 538 billion USD

Question 6

Four scales of measurement

Answer 6

Nominal, ordinal, interval ratio

Question 7

Nominal scale

Answer 7

The variable “values” of the variable can only be described in words, not numbers.
No natural ranking of the categories.
Mathematical: = and =/
EX. fruit, name, gender

Question 8

Ordinal scale

Answer 8

It is not possible to indicate in any meaningful way differences or distances between the values.
Natural ranking of categories.
Mathematical: =,=/, >,<
Ex. grades, education level

Question 9

Interval scale

Answer 9

Variables measured on the interval scale have fixed measurement.
It makes sense to specify differences or distances between values.
Data are numeric, natural ranking.
Arbitrary zero point
Mathematical: =,=/,<,>,+,-
Ex. celsius, year

Question 10

Ratio scale

Answer 10

Variables measured on the ratio scale have fixed measurement units.
It makes sense to specify differences or distances between values.
Always numeric, natural ranking.
Must have a true/absolute zero point.
Mathematical: =,=/,<,>,+,-,*,/
Ex. length, weight, age

Question 11

Population

Answer 11

The population consists of all elements the investigator is interested in

Question 12

Sample

Answer 12

A sample is a subset of the population

Question 13

3 measures of central tendency

Answer 13

A measure of central tendency is a central or typical value for data or a probability function
Mode
Median
Mean

Question 14

Measures of variability

Answer 14

Measures of variability are numeric values that indicate the variation in a data set
Ex. min, max, range; percentiles; variance and standard deviation

Question 15

Range

Answer 15

The range is the absolute value of the difference between the largest and smallest value in the dataset

Question 16

Percentiles

Answer 16

The Pth percentile is the value such that at least p percent of the observations are less than or equal to this value

Question 17

Variance

Answer 17

The variance is the expectation (explained in future lectures) of the squared deviation of a random variable from its mean. It is a measurement of how far a set of observations is scattered around the mean value