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^{K501-Quantitative Analysis for Business Decisions}

^{Md. Ershadul Haque}

^{Associate Professor}

^{Dept. of Statistics, University of Dhaka}

^{02-03 February, 2024}^�

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Sampling Distribution and Estimation: Terminologies

Sampling Distribution and Estimation

Sampling Distribution and Estimation (cont…)

Properties of normal population

The Central Limit Theorem (CLT)

Visualizing CLT

Visualizing CLT (cont…)

Probability of Observing Sample Values for a Hypothetical Population

Confidence Interval

Confidence Interval (cont…)

Sampling Distribution and Estimation (cont…)

Sampling Distribution and Estimation (cont…)

Exercise

Problem#01: As part of their business promotional package, the Milwaukee Chamber of Commerce would like an estimate of the mean cost per month of a one-bedroom apartment. A random sample of 40 apartments currently available for lease showed the mean cost per month was $323. The standard deviation of the sample was $25. (a) Develop a 95 percent confidence interval for the population mean. (b) Would it be reasonable to conclude that the population mean is $350 per month?
Problem#02: A recent study by the American Automobile Dealers Association revealed the mean amount of profit per car sold for a sample of 20 dealers was $290, with a standard deviation of $125. Assuming amount of profit per car sold follows normal distribution, develop a 95 percent confidence interval for the population mean.
Problem#03: During a national debate on changes to health care, a cable news service performs an opinion poll of 500 small-business owners. It shows that 65 percent of small-business owners do not approve of the changes. Develop a 95 percent confidence interval for the proportion opposing health care changes. Comment on the result.