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    Sampling Distribution of Sample Proportion

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    1) A store has determined that 25% of all sales are credit sales. A random sample of 75 sales is selected. What is the probability that the sample proportion will be:
    a) greater than .34?
    b) between .196 and .354?
    c) less than .25?
    d) less than .10?

    2) 10% of items produced by a machine are defective. A random sample of 100 items is selected and checked for defects. What is the probability that the sample will contain:
    a) more than .025?
    b) less than .13 defective units?

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    Solution Preview

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    Probability questions/need answers, but explanation of solution
    1) A store has determined that 25% of all sales are credit sales. A random sample of 75 sales is selected. What is the probability that the sample proportion will be:
    Answers
    Let X be the proportion of credit sales. Then X can be assumed to be normal with mean, µ = ...

    Solution Summary

    The solution provides step by step method for the calculation of probability using z score. Formula for the calculation and shaded graph are also given. Machine defection rates are examined.

    $2.19

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