Week 1 Addendum: Homework/Quiz Review
1. Is each item below an example of descriptive or inferential statistics?
Take a sample of cars and test them to determine how many miles per gallon (mpg)
they give. Use this sample to estimate the mpg of all cars.
Answer: Inferential
To get an idea of student performance on a test, analyze the data in the gradebook
about the test. Answer: Descriptive
2. In each case, identify the type of data (or level of data):
The dollar sales at the local pizza shop each month - Ratio
An employee’s identification number - Nominal
Rating of how satisfied you are with your professor. Possible values are: "very
dissatisfied," "somewhat dissatisfied," "somewhat satisfied," or "very satisfied." -
ordinal
Amount you have won/lost when gambling in Atlantic City (in dollars) - Interval
Color of a car - nominal
3. For the following frequency distribution:
Class Frequency Cumulative
frequency
30-under 40 7 7
40-under 50 10 17
50-under 60 2 19
60-under 70 5 24
24
a. what is the relative frequency for the class “50-under 60”? 0.08 (2/24) or 8%
b. what is the cumulative frequency for the class “50-under 60”? 19
NOTE: To answer the questions above it is helpful to create the following table:
Class Freq Cumulativ
e Freq
Relative Freq
30-under 40 7 7 7/24 = 0.29
40-under 50 10 17 10/24 = 0.42
50-under 60 2 19 2/24 = .08
60-under 70 5 24 5/24 =.21
24 1.00
