Homework Help: statistics

Posted by Anonymous on Wednesday, January 26, 2011 at 10:04am.

The numbers of hours of life of a torch battery is normally distributed with a mean of 150 hours and standard deviation of 12 hours. In a quality control test, two batteries are chosen at random from a batch. If both batteries have a life less than 120 hours, the batch is rejected. Find the probability that the batch is rejected.

statistics - PsyDAG, Wednesday, January 26, 2011 at 11:23am
Z = (score-mean)/SD = (120-150)/12

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion related to that Z score.

The probability of both/all events occurring is found by multiplying the individual probabilities.

I hope this helps.

Answer this Question

Related Questions

statistics - The life span of the battery pack is known to be Normally ...
Statistics - The lifetimes of batteries produced by a firm are known to be ...
math - The lifetime of a SuperTough AAA battery is normally distributed with ...
Math - The lifetime of a SuperTough AAA battery is normally distributed with ...
statistics - Urgen!! Statistics homework help? Your company is producing special...
probability and statistics - An electrical firm manufactures light bulbs that ...
Statistics - An electrical firm which manufactures a certain type of bulb wants ...
statistics - Section 5.3: Normal Distributions: Finding Values Answer the ...
Statistics - The lifetime of a certain smart phone battery has an unknown ...
Statistics - The lifetime of a certain smart phone battery has an unknown ...

For Further Reading

First Name:
School Subject:
Answer: