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Math Help - Maths question - standard distribution

  1. #1
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    Maths question - standard distribution

    The working lie of 60 watt bulbs produced by Max Bulb CVo is normally distributed with a mean of 24.00 hours and a standard deviation of 6.06 hours.

    what is the probability that a bulb at random is picked from this populatiohn with a working life of more than 29.11 hours?

    Thanks
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  2. #2
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    Quote Originally Posted by Pikachu View Post
    The working lie of 60 watt bulbs produced by Max Bulb CVo is normally distributed with a mean of 24.00 hours and a standard deviation of 6.06 hours.

    what is the probability that a bulb at random is picked from this populatiohn with a working life of more than 29.11 hours?

    Thanks
    Obviously you have to calculate Pr(X > 29.11).

    If you provide details on how you've been taught to calculate probabilities such as these (tables, technology, ....?) further specific help can be given.
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  3. #3
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    I agree, find p(X>29.11)

    The question refers to normal distribution so turn into a Z value

    p(Z>(29.11-24)/6.06)

    p(Z>0.95) = 0.17
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