Assignment:
1. Use Bilingual sheet to answer this question.
A national survey of companies included a question that asked whether the company had at least one bilingual telephone operator. The sample results of 90 companies follow (Y denotes that the company does have at least one bilingual operator; N denotes that it does not).
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N
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N
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N
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N
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Y
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N
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Y
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N
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N
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|
Y
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N
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N
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N
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Y
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Y
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N
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N
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N
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N
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N
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Y
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N
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Y
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N
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Y
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N
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Y
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Y
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Y
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N
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Y
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N
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N
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N
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Y
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N
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N
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Y
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N
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N
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N
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N
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N
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N
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N
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Y
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N
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Y
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Y
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N
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N
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Y
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N
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Y
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N
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N
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Y
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Y
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N
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N
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N
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N
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N
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Y
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N
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N
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N
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N
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Y
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N
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N
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N
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Y
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Y
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Y
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N
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N
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Y
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N
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N
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N
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N
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N
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N
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Y
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Y
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N
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N
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Y
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N
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The file Dataset_HW-3, sheet named Bilingual also contains the above survey results. Use this information to estimate with 80% confidence the proportion of the population that does have at least one bilingual operator.
2. Use Part-2 sheet to answer this question.
You are trying to estimate the average amount a family spends on food during a year. In the past the standard deviation of the amount a family has spent on food during a year has been approximately $1000. If you want to be 99% sure that you have estimated average family food expenditures within $50, how many families do you need to survey?
3. Use Part-3 sheet to answer this question.
You have been assigned to determine whether more people prefer Coke or Pepsi. Assume that roughly half the population prefers Coke and half prefers Pepsi. How large a sample do you need to take to ensure that you can estimate, with 95% confidence, the proportion of people preferring Coke within 3% of the actual value? [Hint: proportion est. = 0.5]