Exercise Answer Errors:

[tmastri2]

Ch.1 9b

Original Question:

Question reads as follows:
b. What are the cases in this study and how many are included?

Answer Given:
10 cases: the daycare centers

Revision Suggested:

The dataframe used has a row per center and week combination, which is in line with the definition of tidy data, but this implies that each row needs to be uniquely identified, so the number of cases/observational units is 200 (10 centers * 20 weeks).

(Also might want to include the caveat that an observational unit might not be defined by a single column)

[tmastri2]

Ch.2 5b

Original Question:

Question reads as follows:
b. Comment on whether the results of the study can be generalized to the population, and if the findings of the study can be used to establish causal relationships.

Part of Answer Given:
This is probably not a reasonable assumption since these students are from two specific majors only.

Revision Suggested:

The description of the study doesn't include that only 2 majors were selected. I think the confusion comes from the fact that in Chapter 1 the equivalent question has the major of the student listed as a variable.