Chapter 8: Confidence Intervals for One Population Mean

What is meant by saying that a statistical procedure is robust?

Assume that the population standard deviation is known and decide weather use of the z-interval procedure to obtain a confidence interval for the population mean is reasonable. Explain your answers.

The variable under consideration is very close to being normally distributed, and the sample size is $10$.

Assume that the population standard deviation is known and decide weather use of the $z$interval procedure to obtain a confidence interval for the population mean is reasonable. Explain your answers.

The variable under consideration is very close to being normally distributed, and the sample size is$75$.

Assume that the population standard deviation is known and decide weather use of the $z$-interval procedure to obtain a confidence interval for the population mean is reasonable. Explain your answers.

The sample data contain outliers, and the sample size is$20$.

Assume that the population standard deviation is known and decide weather use of the z-interval procedure to obtain a confidence interval for the population mean is reasonable. Explain your answers.

The sample data contain no outliers, the variable under consideration is roughly normally distributed, and the sample size is $20$.

Assume that the population standard deviation is known and decide weather use of the z-interval procedure to obtain a confidence interval for the population mean is reasonable. Explain your answers

The distribution of the variable under consideration is highly skewed, and the sample size is $20$.

Assume that the population standard deviation is known and decide weather use of the z-interval procedure to obtain a confidence interval for the population mean is reasonable. Explain your answers .

The sample data contain no outliers, the sample size is $250$, and the variable under consideration is far from being normally distributed.

Must the variable under consideration be normally distributed for you to use the z-interval procedure or $t-$interval procedure? Explain your answer.

Express the form of most of the confidence intervals that you will encounter in your study of statistics in terms of "point estimate" and "margin of error."

Suppose that you have obtained data by taking a random sample from a population. Before performing a statistical inference, what should you do?