Acting on faulty measurements could be costly. Requires action only if its probability of being true is low (typically 5%).īefore cutting an expensive piece of granite for a countertop, a good carpenter will first confirm he has measured correctly.So in conclusion, in order to be “Busy Doin’ Nothin’”, your Null Hypothesis has to be as follows: Is Your Null Hypothesis Suitably Inactive? I only need to control the sunshine, temperature and rain if the probability that they have no effect is very small. These all assume that none of these factors impact the strawberry yield. Once I decided that the weather was a combination of sunshine, rain and temperature, I established my null hypotheses. That's because I needed to define some metrics to measure the weather. Note that the last instance in the table, investigating if weather affects the growth of my strawberries, is a bit more complicated. Temperature has no effect on strawberry yield Number of hours sunshine has no effect on strawberry yieldĪmount of rain has no effect on strawberry yield If my bolt diameters are normally distributed I can use any statistical techniques that use the standard normal approach.ĭoes the weather affect how my strawberries grow? If I am giving my customers the right size chocolate bars I don’t need to make changes to my chocolate packing process.Īre the diameters of my bolts normally distributed?īolt diameters are n ormally distributed. Let’s have a look at how this works in practice with some common examples.ĭo the chocolate bars I am selling weigh 100g? When the probability of the Null Hypothesis is very low and we reject the Null Hypothesis, then we will have to take some action and we will no longer be “Doin Nothin'”. The null hypothesis is always the option that maintains the status quo and results in the least amount of disruption, hence it is “Busy Doin’ Nothin'”.
Once we have this, we can then work on defining our Null and Alternative Hypotheses. What's the Question?īefore doing any statistical analysis-in fact even before we collect any data-we need to define what problem and/or question we need to answer. The 1949 film A Connecticut Yankee in King Arthur's Court includes the song “Busy Doing Nothing,” and this could be written about the Null Hypothesis as it is used in statistical analyses.Īnd that summarises the role of the Null Hypothesis perfectly.
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