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August 21, 2014

August 21, 2014

Posted by **Joy** on Sunday, January 22, 2012 at 5:38pm.

9.0 months 7.0 months

8.2 months 8.3 months

7.8 months 8.1 months

7.5 months 7.6 months

9.1 months 7.4 months

I calculated the standard deviation to be about 0.679.

Estimate the probability that a random chosen light will last as long as 7 months after installation. Assume the data to be described by a normal distribution.

Can anyone help me with the process I would use to calculate the answer? Thanks!

- science -
**PsyDAG**, Monday, January 23, 2012 at 11:39amI assume that you have calculated the mean to find the SD.

Z = (score-mean)/SD

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

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