Question 4: What does ‘P=0.02’ mean and what can we conclude here?
This is a the result of a significance test.
We are testing the null hypothesis that the average amounts of alcohol which men and women report drinking are the same in the population, the alternative hypothesis being that there is a difference in mean alcohol reported. P is the probability of getting a difference as far as is 3.2 from the zero which would be expected if the null hypothesis were true.
The P value is small, less than 0.05. We can conclude from this that there is evidence that the null hypothesis is not true and that men and women differ in the mean amount of alcohol they report drinking. However, 0.02 is not small enough for us to say the evidence is strong. We would usually want P to be less than 0.01 to conclude that there was strong evidence.
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