Question

determine which of the four levels of measurements is most appropriate.
course grades: a college professor assigns grades of a, b, c, d or f.
○ ordinal
○ interval
○ ratio
○ nominal

question 2
identify which of these types of sampling is used: random, systematic, convenient, stratified or cluster.
a) testing lipitor: in a clinical of the cholesterol drug lipitor 300 subjects were ran assigned to take the treatment.
select

Explanation:

Question 1

1. Recall the definitions of the four levels of measurement:

• Nominal: Categories with no order or ranking (e.g., colors, genders).
• Ordinal: Categories with a natural order or ranking, but the differences between values are not meaningful (e.g., letter grades, ranks).
• Interval: Numerical values with equal intervals, but no true zero (e.g., temperature in Celsius).
• Ratio: Numerical values with equal intervals and a true zero (e.g., height, weight).

1. Analyze course grades (A, B, C, D, F):

• These grades represent a ranking (A is better than B, B better than C, etc.), so there is a natural order.
• However, the difference between an A and a B is not a fixed, measurable quantity (unlike interval or ratio scales).
• Since there is order but not meaningful differences, this fits the ordinal level.

1. Recall the sampling methods:

• Random Sampling: Subjects are selected randomly (each has an equal chance).
• Systematic Sampling: Selecting every kth subject.
• Convenience Sampling: Using easily accessible subjects.
• Stratified Sampling: Dividing into groups (strata) and sampling from each.
• Cluster Sampling: Dividing into clusters and sampling entire clusters.

1. Analyze the Lipitor study:

• The problem states "300 subjects were randomly assigned to take the treatment." This indicates that subjects were selected randomly for the treatment group, which is characteristic of random sampling (specifically, a randomized experiment, but in terms of sampling the assignment here is random).

Answer:

Ordinal

Question 2 (Part a)