Wednesday

October 1, 2014

October 1, 2014

Posted by **Maggie** on Monday, June 11, 2007 at 1:19am.

The mean life of a brand of auto batteries is 44 months with a standard deviation of 3 months. Assume that the lives of all auto bateries of this brand have a bell-shaped distribution.

1. using empirical rule, find the percentage of auto batteries of this brand that have a life of

a. 41 to 47 months

b. 35 to 53 months

2. using empirical rule, find the interval that contains the mean life of the batteries by 95% of the batteries.

3. One customer says that he used the battery for 52 months. Find the z-score for the 52 month.

I donft know about the 1-1/k^2 empirical rule. However, you can answer all of the questions by using Z scores.

Z = (X - )/SD

where X = raw score, = mean and SD = standard deviation.

Figure the Z scores for each of the raw scores and look up the percentages cut off in the normal distribution. This can be found in a table in the back of your statistics textbook.

I hope this helps. Thanks for asking.

**Answer this Question**

**Related Questions**

Math - I have been stuck on this problem for a while need help on it and soon. ...

calculus - I have been asked to solve this two different ways. The first way is...

Algebra - Ok, so , I have the question: -5=-8+5f. I'ev figured out that I have ...

Math - i have this question on tesselations, I got some homework and one of the ...

Mathematics - I have this question on tesselations, I got some homework and one ...

Chemistry - I've been working on this problem for hours and cant figure it out. ...

physics - I have been stuck on this for a while now and cant figure out what it ...

statistics - Why am I stuck? How do I figure I must be really stressed because I...

appl,ied business research & statistics - When would you use Chebyshevs theorem...

Statistics - For the past week I have been trying to find Canadian statistics ...