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Math Help - Stats: Correct or not?

  1. #1
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    Stats: Correct or not?

    Can someone check my work?

    Q
    1. A recent study found that, at most, 32% of people who have been in a plane crash have died. In a sample of 100 people who were in a plane crash, 38 died. Is the study statement believable?

    Solution:

    H(null): P= 0.32
    H(alternative): P>0.32 Right tailed

    P(hat): 0.38
    P= 0.32
    n= 100

    Then you use the test statistic


    z= P(hat)-P/Sqrt(pq/n)
    z= 0.38-0.32/sqrt(0.32 x 0.68/100)~ 1.29

    So I look for the area on the z score chart and it should be 0.90147. However since that's the area on the left side of the z score. So i must do 1-0.90147= .0985

    .0985<0.05 so Reject H(null).....So the statement is believable right?
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  2. #2
    Eater of Worlds
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    What alpha level are you using?. You didn't say. I assumed .05

    \leq{0.32}" alt="H_{0}\leq{0.32}" />(claim)
    >0.32" alt="H_{a}>0.32" />

    Test stat = 1.2862

    critical value = 1.6449

    p value = 0.0992

    Do not reject the null hypothesis.

    There is not enough evidence at the 5% level to reject the claim that at most 32% of plane crash victims die.

    The claim is valid.

    If you test at alpha = 0.1, then you can reject.
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  3. #3
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    Quote Originally Posted by Nimmy View Post
    Can someone check my work?

    Q
    1. A recent study found that, at most, 32% of people who have been in a plane crash have died. In a sample of 100 people who were in a plane crash, 38 died. Is the study statement believable?

    Solution:

    H(null): P= 0.32
    H(alternative): P>0.32 Right tailed

    P(hat): 0.38
    P= 0.32
    n= 100

    Then you use the test statistic

    z= P(hat)-P/Sqrt(pq/n)
    z= 0.38-0.32/sqrt(0.32 x 0.68/100)~ 1.29

    So I look for the area on the z score chart and it should be 0.90147. However since that's the area on the left side of the z score. So i must do 1-0.90147= .0985

    .0985<0.05 so Reject H(null).....So the statement is believable right?
    Assuming your arithmetic is right wha you have is:

    0.0985>0.05 so we do not reject H(null) at the .....So the statement is believable in that we do not reject the hypothesis at this level.

    RonL

    RonL
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  4. #4
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    Quote Originally Posted by galactus View Post
    What alpha level are you using?. You didn't say. I assumed .05

    \leq{0.32}" alt="H_{0}\leq{0.32}" />(claim)
    >0.32" alt="H_{a}>0.32" />

    Test stat = 1.2862

    critical value = 1.6449

    p value = 0.0992

    Do not reject the null hypothesis.

    There is not enough evidence at the 5% level to reject the claim that at most 32% of plane crash victims die.

    The claim is valid.

    If you test at alpha = 0.1, then you can reject.
    Is that another way you can solve it? Is my work wrong? How did you get the critical value?
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  5. #5
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    Quote Originally Posted by CaptainBlack View Post
    Assuming your arithmetic is right wha you have is:

    0.0985>0.05 so we do not reject H(null) at the .....So the statement is believable in that we do not reject the hypothesis at this level.

    RonL

    RonL
    oh lol you right. I assume it was 0.5 instead of 0.05
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