Give an example of when you would use alpha level 0.05  and when you would use 0.01
in Statistics Answers by

Your answer

Your name to display (optional):
Privacy: Your email address will only be used for sending these notifications.
Anti-spam verification:
To avoid this verification in future, please log in or register.

1 Answer

An alpha or significance level of 0.05 corresponds to a 95% confidence level. 0.01 corresponds to a 99% confidence level. If a vaccine is said to offer 80% immunity to a particular life-threatening disease then at a 95% confidence level, you would be confident in 19 out of 20 samples of vaccinated people that 4 in 5 people in the sample would become immune to the disease. But at a 99% confidence level you would be more confident, that is, in 99 out of 100 samples of vaccinated people that 4 in 5 people would become immune. It's clearly better in what could be a life or death situation to have a higher confidence level (a lower alpha level).

By contrast, consider a weather forecast. A 95% confidence level about the 60% possibility of rain on a particular day isn't usually a life or death situation, although it might have some significance for farmers or mountain climbers, for example, so the degree of confidence may not need to be particularly high. A hurricane or typhoon forecast, however, may need to have a higher confidence level for the safety of a community or shipping, for example, so a 99% confidence level may be preferable (if that's possible).

by Top Rated User (1.0m points)

Related questions

1 answer
1 answer
2 answers
asked Apr 22, 2013 in Word Problem Answers by anonymous | 9.6k views
1 answer
1 answer
1 answer
Welcome to, where students, teachers and math enthusiasts can ask and answer any math question. Get help and answers to any math problem including algebra, trigonometry, geometry, calculus, trigonometry, fractions, solving expression, simplifying expressions and more. Get answers to math questions. Help is always 100% free!
87,024 questions
96,354 answers
24,341 users