1 .The weight of a .5 cubic yard bag of landscape mulch is uniformly distributed over the interval from 38.5 to 41.5 pounds. What is the probability that a bag will weigh less than 41 pounds?
2 . A small stock brokerage firm wants to determine the average daily sales (in dollars) of stocks to their clients. A sample of the sales for 36 days revealed average daily sales of $200,000. Assume that the standard deviation of the population is known to be $18,000.
a. Provide a 90% confidence interval estimate for the average daily sale.
b. Provide a 99% confidence interval estimate for the average daily sale.
3 . Consider the following results for two samples randomly taken from two normal populations with equal variances.
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Sample I
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Sample II
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Sample Size
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28
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35
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Sample Mean
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48
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44
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Population Standard Deviation
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9
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10
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a. Develop a 95% confidence interval for the difference between the two population means.
b. Is there conclusive evidence that one population has a larger mean? Explain.