PSY 380 Introduction to probability
and statistics Question and answers
100% correct 2025/2026
1) As a general rule, a simple frequency distribution should have between - correct answer ✔5-20
intervals
A movie critic rates a movie on a scale from one (lowest) to four (highest) stars. What scale of
measurement are the ratings? - correct answer ✔ordinal
1) The following samples were selected by two researchers. Which is associated with a smaller standard
error of the mean?
Researcher A: n = 25, μ = 5, σ = 7
Researcher B: n = 25, μ = 32, σ = 7 - correct answer ✔They both have the same standard error.
A sample mean is not always equal to a population mean - correct answer ✔true
A researcher computes the definitional formula for SS, and finds that
Σ(x − M) = 44.
If this is a sample of 12 scores, then what would the value of sample variance be using the
computational formula? - correct answer ✔4.0
The use of tables and graphs to summarize data is an example of - correct answer ✔Descriptive
Statistics
All other things being equal (so assuming that the value of SS never changes), as sample size increases, -
correct answer ✔The value of sample variance decrease
and statistics Question and answers
100% correct 2025/2026
1) As a general rule, a simple frequency distribution should have between - correct answer ✔5-20
intervals
A movie critic rates a movie on a scale from one (lowest) to four (highest) stars. What scale of
measurement are the ratings? - correct answer ✔ordinal
1) The following samples were selected by two researchers. Which is associated with a smaller standard
error of the mean?
Researcher A: n = 25, μ = 5, σ = 7
Researcher B: n = 25, μ = 32, σ = 7 - correct answer ✔They both have the same standard error.
A sample mean is not always equal to a population mean - correct answer ✔true
A researcher computes the definitional formula for SS, and finds that
Σ(x − M) = 44.
If this is a sample of 12 scores, then what would the value of sample variance be using the
computational formula? - correct answer ✔4.0
The use of tables and graphs to summarize data is an example of - correct answer ✔Descriptive
Statistics
All other things being equal (so assuming that the value of SS never changes), as sample size increases, -
correct answer ✔The value of sample variance decrease
