3. Interval estimation of a population mean, population standard deviation unknown The Business Environment and Enterprise Performance Survey (BEEPS), developed by the European Bank for Reconstruction and Development and the World Bank, is a survey of more than 4,000 firms in 22 transition countries. Conducted in 2000, BEEPS gathered information on the impediments to business growth in transition countries. As part of BEEPS, firms that export goods answered the question, "How many days does the preshipment inspection take from the time you submit your goods until the time they are released?" For the sample of 46 exporting firms in Turkey, the sample mean x was 2.8 days, and the sample standard deviation s was 3.4 days. The standard deviation of the population distribution is unknown, but you are willing to assume that the population distribution is not highly skewed and contains no outliers.

To develop a 99% confidence interval estimate of the mean number of days it takes for exported goods to be released in Turkey, use the.............. ( ans options are : T distribution with 45, 35,46 degrees of freed, standard normal distribution) .

Use the Distributions tool to compute a 99% confidence interval estimate for the mean number of days it takes for exported goods to be released in Turkey.

You are 99% confident that the mean wait time for exported goods to be released in Turkey is between ___ and__- days.

The confidence interval estimate you calculated is appropriate because:

a. You are assuming the population distribution is not highly skewed nor contains outliers and the sample size is at least 30.

b. Using the t distribution means the sampling distribution of the mean does not need to be normal.

c. The wait time for exported goods to be released in Turkey is normally distributed.