Suppose for every 100 births in a country, the number of boys follows, approximately, a normal curve with a mean of 54 boys and standard dev

Question

Suppose for every 100 births in a country, the number of boys follows, approximately, a normal curve with a mean of 54 boys and standard deviation of 5 boys. If the next 100 births in a hospital in this country resulted in 39 boys (and thus 61 girls), would that be unusual

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Rose 15 hours 2021-10-13T06:07:52+00:00 1 Answer 0

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    2021-10-13T06:09:12+00:00

    Answer:

    Z = -3 means that if the next 100 births in a hospital in this country resulted in 39 boys (and thus 61 girls), it would be considered unusual.

    Step-by-step explanation:

    Problems of normally distributed samples are solved using the z-score formula.

    In a set with mean \mu and standard deviation \sigma, the zscore of a measure X is given by:

    Z = \frac{X - \mu}{\sigma}

    The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

    Values of Z of -2 or lower, or 2 or higher are considered unusual.

    In this problem, we have that:

    \mu = 54, \sigma = 5

    If the next 100 births in a hospital in this country resulted in 39 boys (and thus 61 girls), would that be unusual

    This is Z when X = 39. So

    Z = \frac{X - \mu}{\sigma}

    Z = \frac{39 - 54}{5}

    Z = -3

    Z = -3 means that if the next 100 births in a hospital in this country resulted in 39 boys (and thus 61 girls), it would be considered unusual.

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45:7+7-4:2-5:5*4+35:2 =? ( )