Question #333257

An electrical company claims that an average life of bulbs it manufacturers is 1200 hours with a standard deviation of 250 hours. If a random sample of 100 bulbs is chosen, what is the probability of the sample mean will be:




a. Greater than 1150 hours?




b. Less than 1250 hours?




c. Betweem 1150 and 1250 hours?

1
Expert's answer
2022-04-25T22:55:05-0400

a. P(X>1150)=1P(X<1150)=1P(Z<11501200250/100)=1P(Z<2)=10.0228=0.9772P(X>1150)=1-P(X<1150)=1-P(Z<\frac{1150-1200}{250/\sqrt{100}})=1-P(Z<-2)=1-0.0228=0.9772

b.P(X<1250)=P(Z<12501200250/100)=P(Z<2)=0.9772P(X<1250)=P(Z< \frac{1250-1200}{250/ \sqrt{100}})=P(Z<2)=0.9772

c.P(1150<X<1250)=P(X<1250)-P(X<1150)=0.9772-0.0228=0.9544




Need a fast expert's response?

Submit order

and get a quick answer at the best price

for any assignment or question with DETAILED EXPLANATIONS!

Comments

No comments. Be the first!
LATEST TUTORIALS
APPROVED BY CLIENTS