The lifetimes of a certain brand of photographic light are normally distributed with a mean of 210 h and a standard deviation of 50 h.
a) What is the probability that a particular light will last more than 250 h?
b) What percent of lights will need to be replaced within 235 h?

Question

The lifetimes of a certain brand of photographic light are normally distributed with a mean of 210 h and a standard deviation of 50 h.
a) What is the probability that a particular light will last more than 250 h?
b) What percent of lights will need to be replaced within 235 h?

anonymous · Answer

and c....out of 2000 lights how many will have a lifetime between 200 and 350 hrs

anonymous · Answer

I don't even know where to start trying here...

amistre64 · Answer

i start by drawing a humpback

amistre64 · Answer

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