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# Confidence Interval for Mean & Proportion

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Please show the formula and step used to solve these two problems.

3. A random sample of 10 parking meters in downtown Nashville showed the following incomes for a day.

\$2.60, \$1.05, \$2.45, \$2.90, \$1.30, \$3.10, \$2.35, \$2.00, \$2.40, \$2.35

Find the 95% confidence interval of the true mean.

6. Out of 250 people surveyed, 112 of them are against paddling as a punishment in school. Give a 90% confidence interval for the true proportion of people who are against paddling in school.

https://brainmass.com/statistics/confidence-interval/confidence-interval-mean-proportion-395414

#### Solution Preview

The 95% confidence interval is given by , where = 2.25, = 0.645927413, n = 10, = 2.262157158
Therefore the required CI is given by,

= (1.79, 2.71)
Thus with 95% confidence we can claim that population mean income for a day is within (\$1.79, \$2.71).
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Confidence Interval ...

#### Solution Summary

The solution provides step by step method for the calculation of confidence interval for mean and proportion. Formula for the calculation and Interpretations of the results are also included. Interactive excel sheet is included. The user can edit the inputs and obtain the complete results for a new set of data.

\$2.19