Statistical Inferences Answers

The number of sit-ups that all tenth-grade girls can do in 5 minutes is normally distributed. Beth surveyed 20 of her fellow intramural tennis players, all tenth-grade girls, and determined the mean number of sit-ups they could do. Can she make an inference about the population mean for all tenth-grade girls based on the sample?

What is the z-score with a confidence level of 95% when finding the margin of error for the mean of a normally distributed population from a sample?

Dawn and Pablo are members of a normally distributed population that is being sampled. If the chance of Dawn being included in the sample is 0.05%, what must the chance of Pablo being included in the sample be in order to be able to make inferences about the population based on the sample?

A simple random sample of 60 is drawn from a normally distributed population, and the mean is found to be 28, with a standard deviation of 5. Which of the following values is within the 95% confidence interval (z-score = 1.96) for the population mean?Remember, the margin of error, ME, can be determined using the formula .

Suppose the mean of a normally distributed population is 300, and 200 simple random samples are drawn from the population. At a 68% confidence level, (one standard deviation from the mean), about how many of the samples’ confidence intervals would you expect to contain the population mean?

Which of the following z-values, standard deviations, and sample sizes produce a margin of error of 0.95?

All else being equal, if you cut the sample size in half, how does this affect the margin of error when using the sample to make a statistical inference about the mean of the normally distributed population from which it was drawn?.

Jason and Yolanda both drew a simple random sample from a non-normally distributed population of 25,000. Jason’s sample consisted of 0.24% of the population, while Yolanda’s sample consisted of 0.32% of the population. Whose sample can be used to make inferences about the population?

A simple random sample is drawn from a normally distributed population. The value of which of the following will not be known for certain but can be inferred?

Which of the following conditions must be met in order to make a statistical inference about a population based on a sample if the sample does not come from a normally distributed population?

The times it took for 35 loggerhead sea turtle eggs to hatch in a simple random sample are normally distributed, with a mean of 50 days and a standard deviation of 2 days. Assuming a 95% confidence level (95% confidence level = z-score of 1.96), what is the margin of error for the population mean?Remember, the margin of error, ME, can be determined using the formula .