Description
A particular brand of calc. battery is approx. normally distributed with a mean of 80 hrs and a standard deviation of 9 hours.
a) What is the probability that a single battery randomly selected from the population will have a life between 70 & 90 hrs?
P(70<x<90) = ?
b)What is the probability that 4 batteries from the population will have a sample mean life of between 70 & 90 hrs?
P(70<x<90)= ?
c) Reduce the standard deviation from 9 to 7 hrs. 4 randomly selected batteries
P(70<x<90)= ?
Explanation & Answer
a90-70= 20%
b s=4
s= 10/ sqrt 4=5
c
Review
Review
24/7 Homework Help
Stuck on a homework question? Our verified tutors can answer all questions, from basic math to advanced rocket science!
Similar Content
Related Tags
Cat on a Hot Tin Roof
by Tennessee Williams
The Point of it All - A Lifetime of Great Loves and Endeavors
by Charles Krauthammer
Hiroshima
by John Hersey
Dune
by Frank Herbert
Persuasion
by Jane Austen
Crime and Punishment
by Fyodor Dostoyevsky
To the Lighthouse
by Virginia Woolf
Mockingjay
by Suzanne Collins
Wuthering Heights
by Emily Brontë