36 Selecting an analysis

Selecting the correct confidence interval or hypothesis test can be challenging, and this book only describes a small number of possible scenarios. For the situations studied in this book, determining the number of variables and the types of variables (qualitative or quantitative) is important (Table 36.1).

So far, only descriptive and relational RQs have been studied. The next two chapters consider correlational RQs (Sect. 2.6). Appendix C may also prove useful.

TABLE 36.1: Five scenarios studied so far, plus one to follow.
Summaries
Analysis
Graphical display Numerical summary Confidence interval Hypothesis test
Descriptive RQ: Proportion in one sample (i.e., one qualitative variable)
Bar charts; pie chart Counts; percentages; odds CI for one mean One-sample \(z\)-test
Descriptive RQ: Mean of one sample (i.e., one quantitative variable)
Histogram; stemplot; dot chart Means, medians; Std. dev., IQR; outliers CI for one mean One-sample \(t\)-test
Repeated-measures RQ: paired quantitative data
Histogram of differences; case-profile Mean, std. dev. etc. of differences CI for mean difference \(t\)-test for mean differences
Relational RQs: comparing quantitative variables
Error bar chart Mean and std. error of the difference; mean, std. dev. etc. of each group CI of the difference between two means \(t\)-test for the difference between two means
Relational RQs: comparing qualitative variables
Side-by-side bar chart; stacked bar chart Odds; OR; percentages CI for odds ratios \(\chi^2\)-test for OR
Correlational RQs
Scatterplot Correlation CI for regression parameters Correlation; regression

36.1 Exercises

Answers to odd-numbered exercises are available in App. E.

Exercise 36.1 Suppose researchers compare the mean number of hours of exercise per week for British office workers, both in summer and in winter, to see if the means are different.

What methods would be a suitable for creating a summary and performing analyses?

Exercise 36.2 Suppose researchers wish to estimate the difference between the mean number of hours of sunlight exposure per day for female and male teachers in Denmark.

What methods would be a suitable for creating a summary and performing analyses?

Exercise 36.3 Suppose researchers wish to compare the proportion of trees housing koalas in an Australian national park, comparing trees more than \(10\)tall with trees \(10\)or shorter.

What methods would be a suitable for creating a summary and performing analyses?

Exercise 36.4 Suppose researchers are wanting to estimate the difference between the mean number of hours spent on social media for Indian people aged over \(30\), to people aged \(30\) and under.

What methods would be a suitable for creating a summary and performing analyses?

The following short video may help explain some of these concepts. Note that the test for correlation and regression have not yet been covered in this book (but they will be in the next few chapters).