A&X Electrical makes a lamp. The Research department found that the life of the lamp is normally distributed with a mean of 5000 hours and a standard deviation of 450 hours.

2. What is the probability a lamp will last more than 4000 hours?

Answer: z=4000-5000/450=-2.2
to find area to the right of z we say P(z-2.22)=1-.0132= .9868?

Question

A&X Electrical makes a lamp.  The Research department found that the life of the lamp is normally distributed with a mean of 5000 hours and a standard deviation of 450 hours.

2. What is the probability a lamp will last more than 4000 hours?

Answer: z=4000-5000/450=-2.2
to find area to the right of z we say P(z>-2.22)=1-.0132= .9868?

ganeshie8 · Answer

$\large \color{red}{\checkmark}$

jim_thompson5910 · Answer

you are correct and here is one calculator to confirm http://www.wolframalpha.com/input/?i=P(z%3E-2.22)

anonymous · Answer

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