Torturing numbers: Basic statistics for growers

Spring and fall are conference and lecture season in agriculture, and this is when we’re presented by a flurry of PowerPoint  research results. Sometimes it’s agrichemical reps promoting new pesticides. It could be seed dealers comparing yields. Maybe it’s equipment dealers illustrating return on investment or some efficiency. Even university research and government extension have been known to flash the occasional graph from time to time.

I was asked to develop a talk for Ontario’s tomato growers. It was intended to give a basic grounding in descriptive statistics. More to the point, it would give the grower the tools they needed to raise the red flag when they felt a presenter was, perhaps, not being completely honest. Without a basic understanding of how data can be abused, we are at the mercy of those presenting the data.

  • Did they do their stats correctly?
  • Are they hiding something?
  • Are they skewing something to make us see what they want?

I often raise my hand during presentations where product claims are made. I’ll ask horrible questions about “n“, standard error bars and the scale used on the graphs… Fair warning if I’m in your audience.

I have since been asked to deliver to several grower groups, which was surprising, because no one I know loves statistics.

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So, remember it’s OK to be skeptical of data. Ask questions and dig deeper.