A Survey Was Conducted with Customers of Two Gas Suppliers

Multiple Choice

A survey was conducted with customers of two gas suppliers - Atomic Gas and English Gas. The objective was to assess whether one group of customers spent more (in £s) on their annual gas bill than the other. Initial tests suggested the absence of normality in the dependent variable. A non-parametric test was deemed appropriate, but which do you think that the researchers should use?

A) Paired t-test
B) Mann-Whitney test
C) Wilcoxon signed-rank test
D) Independent t-test