Statistical Inferences - Quiz
A simple random sample is drawn from a normally distributed population, and when making a statistical inference about the population mean, the margin of error is found to be 5.9 at a 95% level of confidence. If the mean of the sample is 18.7, what is the 95% confidence interval for the population mean? 18.7 ± 5.9 18.7 ± 9.7 18.7 ± 11.6 18.7 ± 15.2
A
A simple random sample of 85 is drawn from a normally distributed population, and the mean is found to be 146, with a standard deviation of 34. Which of the following values is outside the 99% confidence interval for the population mean? Use the table below to help you answer the question.Confidence Level90%95%99%z*-score1.6451.962.58Remember, the margin of error, ME, can be determined using the formula . the value of 135 because it is not greater than 136.5 the value of 137 because it is greater than 136.5 the value of 138 because it is less than 153.2 the value of 154 because it is greater than 153.2
A
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?. The margin of error is multiplied by . The margin of error is multiplied by . The margin of error is multiplied by 0.5. The margin of error is multiplied by 2.
B
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? No, because the sample size was not big enough. No, because she did not use a simple random sample. Yes, because the sample size was big enough. Yes, because she used a simple random sample.
B
Which of the following z-values, standard deviations, and sample sizes produce a margin of error of 0.95? z = 2.14; s = 4; n = 9 z = 2.14; s = 4; n = 81 z = 2.14; s = 16; n = 9 z = 2.14; s = 16; n = 81
B
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? 0% greater than 0% and less than 0.05% 0.05% greater than 0.05%
C
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? 0.99 1.65 1.96 2.58
C
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?
C
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 . 0.06 0.11 0.34 0.66
D
Which of the following statements is correct? Population parameters are used to make inferences about sample statistics. Population statistics are used to make inferences about sample parameters. Sample parameters are used to make inferences about population statistics. Sample statistics are used to make inferences about population parameters.
D
