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# Sample Size

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Subject: sample sizing
Details: a local bus company recently started a campaign to encourage people to increase car pooling or use of public transportation. To assess the effectiveness of a campaign, management wanted to do a survey to determine the proportion of people who had adopted the reccommended energy-saving measures.
a) What sample size would you reccommend if the error is not to exceed plus or minus 5 percentage points and the confidence level is to be 90 percent? Show your calculations.
b) The survey indicated that the proportion adopting the measures was 20%. Estimate the 90% confidence interval. Show your calculations.
c) Explain the results in parts A and B.

#### Solution Preview

A local bus company recently started a campaign to encourage people to increase car pooling or use of public transportation. To assess the effectiveness of a campaign, management wanted to do a survey to determine the proportion of people who had adopted the reccommendedenergy-saving measures.

a) What sample size would you reccommend if the error is not to exceed plus or minus 5 percentage points and the confidence level is to be 90 percent? Show your calculations.

This is a two tailed test since we are testing whether sample proportion will not differ from the true population ...

#### Solution Summary

The solution calculates the sample size in a survey to determine the proportion of people who had adopted the reccommended energy-saving measures.

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