the mean is 7 hours and the standard deviation is 1 hour
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

Assuming a normal distribution we can calculate a Z score=(X-m)/s, where X=9.4hr, m=pop mean=7hr, s=pop standard deviation=1hr.


p(≤2.4)=99.18% (from tables).

So p(≥2.4)=100-99.18=0.82%.

by Top Rated User (816k points)

Related questions

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!
86,016 questions
91,947 answers
23,907 users