Statistical Inferences Assignment and Quiz 100%

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%

0.05%

There were 324 adults surveyed. Among the participants, the mean number of hours of sleep each night was 7.5 and the standard deviation was 1.6. The margin of error, assuming a 95% confidence level, is approximately . Round to the nearest hundredth

0.17

Among 420 randomly selected employees at a company, the mean number of hours of overtime worked per month is 10 hours and the standard deviation is 1.6. What is the margin of error, assuming a 99% confidence level? 4.12 0.01 0.20 20.5

0.20

Among 320 randomly selected airline travelers, the mean number of hours spent travelling per year is 24 hours and the standard deviation is 2.9. What is the margin of error, assuming a 90% confidence level? Round your answer to the nearest tenth.

0.3

When finding the margin of error for the mean of a normally distributed population from a sample, what is the critical probability, assuming a confidence level of 86%? 0.14 0.86 0.93 0.99

0.93

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

1.96

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? 64 96 136 204

136

In a random sample of 520 adults, the mean was 150 and the standard deviation was 4.5. The study was reported with a 95% confidence level, and the confidence interval for the study was 150 ± 0.39. What range of values shows the confidence interval for the study? 146.1 to 153.9 149.61 to 150.39 150 to 150.39 150 to 153.9

149.61 to 150.39

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

18.7 ± 5.9

The confidence interval is ____ to ____.

7.33 7.67

A confidence level of 95% means: 95% of the time, sample percentages will fall above the mean. 95% of the time, population data will fall between 149.61 and 150.39. the mean of 95% of the adults in the sample was 150.

95% of the time, population data will fall between 149.61 and 150.39.

Now assume a 95% confidence level. Without performing any calculations, complete the sentence below. The margin of error for a 95% confidence level will be

Greater than 0.3

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.

No, because she did not use a simple random sample.

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?

a

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? neither Jason's sample nor Yolanda's sample only Jason's sample only Yolanda's sample both Jason's sample and Yolanda's sample

both Jason's sample and Yolanda's sample

Which of the following criteria are necessary conditions for making a statistical inference? sample size greater than 30, or an approximately normal data set sample size greater than 100 convenience sample simple random sample systematic sample

sample size greater than 30, or an approximately normal data set simple random sample

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.

the margin of error is multiplied by √2

You are told that in a sample of size 225 the mean is 48.5 and the standard deviation is 1.8. The study is reported with 90% confidence level. Explain how to determine if 48.8 is within the confidence interval.

To find the margin of error, multiply the z-score by the standard deviation, then divide by the square root of the sample size. The z*-score for a 90% confidence level is 1.645. The margin of error is 0.20. The confidence interval is 48.3 to 48.7. 48.8 is not within the confidence interval.

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 M E = StartFraction z times s Over StartRoot n EndRoot EndFraction. The value of 26, because it's not greater than 26.7 and less than 29.3. The value of 27, because it's greater than 26.7 and less than 29.3. The value of 32, because it's greater than 23 and less than 33. The value of 34, because it's not greater than 23 and less than 33.

The value of 27, because it's greater than 26.7 and less than 29.3.