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#1 Re: Help Me ! » Older woman back in school, can not figure out Math probability. » 2010-01-06 05:15:54

I am at work right now.  I don't have what I did with me.  All i can remember is that I created some sort of graph and tried some formulas in the text.  I keep getting the same answers.

I had asked someone here to take a look and they came up with 0.1515 for the first part and 0.8485 for the second.

#2 Help Me ! » Older woman back in school, can not figure out Math probability. » 2010-01-06 01:20:48

lovely lady 74
Replies: 4

The xyz company tested a new product and founds its lifetime to be normally distributed, with a mean life of 146 days and a standard deviation of 19.5 days. What is the probability that a product selected at random will last longer than 166 days?

The answer I can up with is 0.3485 is this correct?

Also for the same company what is the probability that the product will last between 154 and 180 days?

The answer I came with is 0.200 is this correct?

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