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Math Help - Math help needed ASAP please

  1. #1
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    Question Math help needed ASAP please

    Can anyone help me understand how to do these questions?

    I f the number of meals served in a hospital is a normal distribution with amean of 250 and a standard deviation of 37

    a) What is the probability that more than 300 meals are served?
    B) For the middle 50% of the distribution, what is the range of the number of meals served?
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  2. #2
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    a) Hint: 300 is \frac{50}{37} = 1.35135... standard deviations away from the mean.

    b) There is a number a such that the interval (250 - a, 250 + a) comprises 50% of the distribution. Determine a in terms of the standard deviation.

    Using this information, you can find both answers with a table.
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  3. #3
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    I still don't understand, what do I use for a table?
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  4. #4
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    Quote Originally Posted by bathola View Post
    I still don't understand, what do I use for a table?
    If you don't have a table, then you need to use the probability density function for the normal distribution.
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  5. #5
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    Question I am doomed

    What is a probability density function for the normal distribution? Sorry, I have no background with this stuff, and I really don't have a clue how to do it? Can you help me further?
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  6. #6
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    In general, a probability density function is a function of x. If the probability density function for a random variable x is given by p(x),
    then \int _a ^b p(x) \cdot dx gives you the probability that x is between a and b. Have you never seen this before?
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  7. #7
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    Quote Originally Posted by icemanfan View Post
    In general, a probability density function is a function of x. If the probability density function for a random variable x is given by p(x),
    then \int _a ^b p(x) \cdot dx gives you the probability that x is between a and b. Have you never seen this before?
    No, never. I am not able to complete this problem...I am so lost.
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  8. #8
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    Suffice it to say that the probability density function for the normal distribution is a specific probability density function that describes the normal distribution in particular. If you don't know what that function is, and you don't have a table, then I'm not sure how you're supposed to solve the problem either.
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  9. #9
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    Quote Originally Posted by icemanfan View Post
    Suffice it to say that the probability density function for the normal distribution is a specific probability density function that describes the normal distribution in particular. If you don't know what that function is, and you don't have a table, then I'm not sure how you're supposed to solve the problem either.

    Where do you get a table? If I had a table how do I use it?
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  10. #10
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    Quote Originally Posted by bathola View Post
    Where do you get a table? If I had a table how do I use it?
    Most statistics books have tables in the back that give you the information you need to solve problems relating to specific types of distributions, the normal distribution being the most common.

    For instance, I have a table in my statistics book that gives me the probability of x being farther than 1.35 standard deviations from the mean in the positive direction, which is the answer to (a).
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  11. #11
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    Quote Originally Posted by icemanfan View Post
    Most statistics books have tables in the back that give you the information you need to solve problems relating to specific types of distributions, the normal distribution being the most common.

    For instance, I have a table in my statistics book that gives me the probability of x being farther than 1.35 standard deviations from the mean in the positive direction, which is the answer to (a).
    Ok, so is a 0.4115?
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  12. #12
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    Quote Originally Posted by bathola View Post
    Ok, so is a 0.4115?
    No, it's much less than that.
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  13. #13
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    Quote Originally Posted by icemanfan View Post
    No, it's much less than that.
    I have a t distribution chart, and a z Areas under the normal curve chart, is this what I should be using?
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  14. #14
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    Quote Originally Posted by bathola View Post
    I have a t distribution chart, and a z Areas under the normal curve chart, is this what I should be using?
    You shouldn't be using a T-distribution chart for this. Everything relates to the normal distribution.
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  15. #15
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    Quote Originally Posted by icemanfan View Post
    You shouldn't be using a T-distribution chart for this. Everything relates to the normal distribution.
    Can you show me the whole question completed so I can try to figure out how to do it? Thx.
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