2012 --STAT1010 Assignment 1--
Prof. Tsang
Following are suggested answers. Some may have other answers in specific situation if you can explain it.
1. Below is a list of variables (and their possible values). Which of these variables are quantitative and which are
qualitative? Out of the four possible scales of data (Nominal, Ordinal, Interval, Ratio), which scale does each of
them belong to? Explain your answer.
a. The dollar amount on an accounts receivable invoice.
Quantitative
b. The grade (A B C D E F).you may get from this class. Qualitative
c. The stock exchange on which a company’s stock is traded.
d. The total debt of the Italian government in 2010.
ratio
ordinal
Qualitative
Quantitative
Nominal
ratio
e. The advertising medium (radio, television, or newspaper) through which the consumer learned about a product.
Qualitative
Nominal
f. The rating of a movie (very good, good, average, bad, very bad). Qualitative
g. The net profit for a company in 2009.
Quantitative
h. The marital status (Single, Married) of a person.
ordinal
ratio
Qualitative
Nominal
i. The education level of a person (Elementary School, Middle School, College/university, Graduate School).
Qualitative
ordinal
j. The date of birth of a student (e.g. Jan 17, 1994).
Qualitative
k. A factory rates its worker with a scale: skilled, semi-skilled, unskilled.
ordinal
Qualitative
ordinal
l. The radioactivity in radioactive material is commonly measured by the amount of intrinsic radiation activity in
becquerels (one Bq of radioactive material is that amount which has an average of one nuclear disintegration per
second).
Quantitative
ratio
2. Choose the correct answer in the following.
a. An investigator studies how memory changes with age. Age is a (discrete/continuous) variable.
b. A researcher studies the factors that determine how many children couples decide to have. The variable, number
of children, is a (discrete/continuous) variable.
c. The amount of pollutants in water or air (commonly measured as parts per million (ppm)) is a
(discrete/continuous) variable.
d. The average dose received by a person from naturally occurring background nuclear radiation as measured by
mSv/yr (milli-Sievert/year) is a (discrete/continuous) variable.
3. A questionnaire asks individuals to report birthday, gender, eye-color, weight and height. For each of the five
variables:
a. Classify the variable as either discrete or continuous.
b. Identify the scale of measurement that would be used.
birthday, discrete ordinal
gender, discrete nominal
eye-color, discrete nominal
weight, continuous ratio
height, continuous ratio
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2012 --STAT1010 Assignment 1--
Prof. Tsang
4. A researcher records the number of errors per hour each factory worker makes while performing an assembly
line task.
a. Is the researcher measuring a discrete or a continuous variable? discrete
b. What scale of measurement is being used? ratio
The researcher then calculates the average errors per hour for each worker from the data he collected.
c. Is the average errors per hour for each worker a discrete or a continuous variable? continuous
d. What scale is being used? ratio
5. Two researchers are evaluating taste preferences among three leading brands of soft drink. After the subjects
taste each brand, the first researcher asks each subject to identify the most preferred, the second most preferred,
and the least preferred drink. Discrete ordinal
The second researcher asks each subject to rate each of the drinks on a 10-point scale, where a rating of 1 indicates
“terrible taste” and 10 indicates “excellent taste.” Discrete ordinal
Identify the variables both researchers used (discrete or continuous variable) and the scale used in each variable.
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