Important Elements of Statistical Inference:
Statistical Significance/p values; Confidence Intervals
Instructional Video: Statistical Significance
Instructional Video: Confidence Intervals
Stat Lab Exercise #2:
“One Sample t-test”
History/Origins of t testing
Instructional Video
One Sample t test (Concept/Example)
Analytic Platform Options for One Sample t test
Instructional Video
One Sample t test in SPSS
Instructional Video
One Sample t test in Excel
Scenario
A statistics professor was interested to know if the quantitative scores on the GRE of graduate students enrolled in his course were statistically significantly different than the state “norm”. The state norm for the GRE score of students enrolled in College of Education graduate programs was 525. The following represent the GRE scores of students enrolled in the professor’s stats class:
457 500
445 439
630 531
459 387
512 417
503 547
424 511
526 472
573 467
492 523
421 531
536 437
541 503
486 389
517 477
SPSS Data File
For
Stat Lab #2 (One Sample t test)
Assignment
⦁ What was the “Mean Score Difference” between the professor’s class and the state norm on the GRE? Did the difference favor the professor’s class?
⦁ Are the professor’s data “normally distributed”? Provide statistical rationale for your response…
⦁ Was the difference in “Mean Scores” statistically significant? What was the probability (p) level in the comparison? Explain the statistical significance level in the scenario in “layman’s terms”…
⦁ In light of the scenario’s outcome, how should the professor respond to the “Null Hypothesis (H0)” for the scenario’s research question (“Will there be a difference in his class’ GRE scores from the state norm?)
⦁ If an Alternative Hypothesis (Ha) were stated prior to the study as, “There will be a statistically significant difference in GRE scores favoring the professor’s class over the state norm”, how would the professor respond?
⦁ Effect size is an important factor that supplements the interpretation of the statistical significance of finding… Using the following formula and imbedded resources, what would be the magnitude of effect (Effect Size) or Cohen’s d value for the scenario’s finding? …. And, would that Effect Size be classified as “small’, “medium”, and “large”?
d = Mean Score Difference (Professor’s Class – State Norm)
Standard Deviation
Resources
*Instructional Videos/Article: Cohen’s d Effect Size
http://staff.bath.ac.uk/pssiw/stats2/page2/page14/page14.html
*Instructional Video: Cohen’s d Effect Size Calculator
One Sample t test
⦁ Summary of Finding
(in APA format as noted in the PP for the One Sample t test)
⦁ Output
