Category Archives: Sample Size

Effect Sizes, FTW!

Today I give my favourite lecture of the year. Second year students today will be introduced to some of the controversies surrounding the use of p-values. Although I don’t go into great depth, I highlight that p-values—among the many problems associated with them—don’t provide answers to the type of questions we—as researchers—are asking. Continue reading

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The Importance of an Adequate Sample Size

The new year is here! For me, this signals the approaching start of a year 2 research methods module that I run at Keele University. The module consists of weekly lectures and weekly lab classes, wherein students engage with classic-experiment replication and statistical analysis.

Towards the end of the semester, students break into groups of three and initiate a small research (experimental) project addressing a cognitive research question. When students get to the planning stage of their experiment, instructors always hear the same question: “How many participants do we need?”. They look at us eagerly awaiting some peal of wisdom (and a direct answer to their question), but are disappointed to hear the response: “It depends”. Continue reading

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