Posted by MARIA on Monday, January 9, 2012 at 10:47pm.
A new extendedlife light bulb has an average service life of 750 hours, with a standard deviation of 50 hours. If the service life of these light bulbs approximates a normal distribution, about what percent of the distribution will be between 600 hours and 900 hours?

statistics  MathGuru, Tuesday, January 10, 2012 at 4:27pm
Use zscores.
Formula:
z = (x  mean)/sd
Find two zscores, using 600 for x and also 900 for x. Mean = 750 and sd = 50.
Once you find the two zscores, use a zdistribution table to determine your probability between the two zscores.

statistics  sam, Friday, November 18, 2016 at 2:23pm
3 3
Answer This Question
Related Questions
 Stats  A new extendedlife light bulb has an average service life of 750 hours...
 Statistics  Construct a 99% confidence interval for life expectancy of a new GE...
 statisitics  A company installs 5000 light bulbs, each with an average life of ...
 math  1) A light bulb producing company states that its lights will last an ...
 statistics, help  Can someone help me which way can I approach this problem. A ...
 stat  A company installs 5000 light bulbs, each with an average life of 500 ...
 maths  the life span of an electric bulb is normally distribution with mean ...
 Math  A consumer buys n light bulbs, each of which has a lifetime that has a ...
 Math  A consumer buys n light bulbs, each of which has a lifetime that has a ...
 Statistics  An electrical firm which manufactures a certain type of bulb wants ...
More Related Questions