Final answer:
In statistical hypothesis testing, suitable samples must not differ more than 5 mg (option a).
Step-by-step explanation:
In statistical hypothesis testing, two suitable samples must not differ more than 5 mg.
This means that if the difference between two samples is more than 5 mg, it would suggest that there is a significant difference between the two populations or treatments being compared.
For example, if we are comparing the effectiveness of two different medications on blood pressure control and the difference in average blood pressure reduction between the two groups is greater than 5 mg, it would indicate that there is a significant difference in the effectiveness of the medications.
Hence, the answer is option a.