The document discusses the differences between questions of difference, relationship, and goodness of fit. It provides examples to illustrate each type of question. A question of difference compares two or more groups on some outcome, like comparing younger and older drivers' average driving speeds. A question of relationship examines whether a change in one variable causes a change in another, such as the relationship between age and flexibility. A question of goodness of fit assesses how well a claim matches reality, such as whether a salesman's claim of software effectiveness fits the results of user testing.

1. Is this a question of:
Difference? Relationship? Goodness of Fit?

2. Difference –
How do two or more groups (younger/older drivers) compare with
one another in terms of some outcome (average driving speed)?
Central Tendency, Spread, or Symmetry?
vs.

3. Difference –
How do two or more groups (younger/older drivers) compare with
one another in terms of some outcome (average driving speed)?
Central Tendency, Spread, or Symmetry?
Relationship –
Does an increase in one characteristic (age) cause a change in
another characteristic (flexibility)?
vs.

4. Difference –
How do two or more groups (younger/older drivers) compare with
one another in terms of some outcome (average driving speed)?
Central Tendency, Spread, or Symmetry?
Relationship –
Does an increase in one characteristic (age) cause a change in
another characteristic (flexibility)?
Goodness of Fit –
Does your claim (4 out of 5 dentist recommend flavored floss) fit
reality (3 out of 5 of your dentist friends recommend flavored floss)?
vs.
fitDoes the CLAIM . . . REALITY?

5. Let’s Practice!

6. Difference Relationship Goodness of Fit
Does employee morale increase significantly the
longer they work at this company? You sample a
group of 45 and generalize the results.

7. Difference Relationship Goodness of Fit
Does employee morale increase significantly the
longer they work at this company? You sample a
group of 45 and generalize the results.

8. Difference Relationship Goodness of Fit
Does employee morale increase significantly
the longer they work at this company? You
sample a group of 45 and generalize the results.

9. Difference Relationship Goodness of Fit
Does employee morale increase significantly
the longer they work at this company? You
sample a group of 45 and generalize the results.
Relationship –
Does an increase in one characteristic (time worked) cause a
change in another characteristic (employee morale)?

10. Next Example

11. How do management and staff compare in
terms of work satisfaction? You sample both
groups and generalize the results.
Difference Relationship Goodness of Fit

12. How do management and staff compare in
terms of work satisfaction? You sample both
groups and generalize the results.
Difference Relationship Goodness of Fit

13. How do management and staff compare in
terms of work satisfaction? You sample both
groups and generalize the results.
Difference Relationship Goodness of Fit
Difference –
How do two or more groups (management/staff) compare
with one another in terms of some outcome (work
satisfaction)?

14. How do management and staff compare in
terms of work satisfaction? You sample both
groups and generalize the results.
Difference Relationship Goodness of Fit
Difference –
How do two or more groups (management/staff) compare
with one another in terms of some outcome (work
satisfaction)?

15. Final Example

16. A salesman claims that 95% of employees
increase their work productivity using his
software. You test that claim with a sample of 26
employees and find that 86% increase their
productivity.
Difference Relationship Goodness of Fit

17. A salesman claims that 95% of employees
increase their work productivity using his
software. You test that claim with a sample of 26
employees and find that 86% increase their
productivity.
Difference Relationship Goodness of Fit

18. A salesman claims that 95% of employees
increase their work productivity using his
software. You test that claim with a sample of 26
employees and find that 86% increase their
productivity.
Difference Relationship Goodness of Fit
Goodness of Fit –
Does your claim (95% increase work productivity) fit reality
(86% increase work productivity)?

19. A salesman claims that 95% of employees
increase their work productivity using his
software. You test that claim with a sample of
26 employees and find that 86% increase their
productivity.
Difference Relationship Goodness of Fit
Goodness of Fit –
Does your claim (95% increase work productivity) fit reality
(86% increase work productivity)?

20. Is your question a question of:
Difference? Relationship? Goodness of Fit?