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  1. N

    Statisitics - Assocations

    Homework Statement You are working on the continuing study examining low birthweight infants that your Stats professor keeps talking about. He hands you the dataset and asks you some seemingly simple questions. First, he wants to know, is there an association between sex of and...
  2. N

    Probability: Given the Mean and Standard deviation

    Homework Statement The distribution of a drugs among addicts with autoimmune disorder is N(6.9, 16.81). What is the probability that one of these addicts enters your office and reports taking 16 drugs or more? The Attempt at a Solution z = (16-6.9)/4.1 = 2.21 P(z >16) = 0.014 from...
  3. N

    Range of the middle 75% of the data

    Right, There will be 12.5% between infinity and each Z-score. There is 37.5% between each z-score and the mean Don't i still look look for .125 making the middle 75% between Z = 1.15 and Z = -1.15. (from z-table) Therefore, 9.1 - (1.15)(2.14) to 9.1 + (1.15)(2.14) = 6.61 through 11.6 making...
  4. N

    Range of the middle 75% of the data

    Wait I think I have it now There will be 12.5% between the mean and each Z-score,so we look for .125. The closest Z is .32, so the middle 75% is between Z = 0.32 and Z = -32. Therefore, 9.1 - (0.32)(2.14) to 9.1 + (.32)(2.14) = 8.41 through 9.78.
  5. N

    Range of the middle 75% of the data

    Thank you so much. I think I understand I want the x value that cuts off the upper 75% of the curve P(X>x) = 0.75 So I went to the z-table, and got a z value of 0.67 (using 0.251 inside the table, or should i use 0.248) 0.67 = x-9.1/2.14 x= .67(2.14) + 9.1 x= 10.54 therefore, the...
  6. N

    Range of the middle 75% of the data

    Homework Statement Homework Equations TO find the kth percentile =nk/100 (where k=kth percentile and n is the number of observations Need n? Given: n(50)/100 = 9.3 n=18.6 Can n not be an integer? Then I planned on plugging the n into the formula to solve for the 75th percentile...
  7. N

    Mean, median or mode

    Homework Statement You are asked to estimate of the most common level of a ace-inhibitor taken by patients who take the drug. Give your best estimate of central tendency. These are the measurements 0.0 12.5 13.6 14.5 12.0 13.2 0.0 0.0 13.1 14.2 12.5...
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