SOLUTION: A company manufacturing light bulbs claims that an average light bulb lasts 300
days. A potential customer randomly selects 15 bulbs for testing. The sampled bulbs
last an averag
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-> SOLUTION: A company manufacturing light bulbs claims that an average light bulb lasts 300
days. A potential customer randomly selects 15 bulbs for testing. The sampled bulbs
last an averag
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Question 927115: A company manufacturing light bulbs claims that an average light bulb lasts 300
days. A potential customer randomly selects 15 bulbs for testing. The sampled bulbs
last an average of 290 days, with a standard deviation of 50 days. If the company’s
claim were true, what is the probability that 15 randomly selected bulbs would have
an average life of no more than 290 days? Answer by ewatrrr(24785) (Show Source):
You can put this solution on YOUR website! mean = 300
P(x ≤ 290) = P( z < -10/(50/sqrt(15)) =P(z < -.7746)
Using a TI calculator 0r similarly a Casio fx-115 ES plus
P(x ≤ 290) =P(z < -.7746) = normalcdf(-100, -.7746)= .2193 0r 21.93%
