Statistical Inferences Answers

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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

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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.

The confidence interval is [___] to [___].

Answer:

0.27 to 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

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

What is the margin of error, assuming a 90% confidence level? Round your answer to the nearest tenth.

Answer:

2.6

The margin of error for a 95% confidence level will be greater than 0.3.less than 0.3.equal to 0.3.

greater than 0.3.

less than 0.3.

equal to 0.3.

The margin of error, assuming a 95% confidence level, is approximately . Round to the nearest hundredth

Answer:

0.04

The confidence interval is ⇒ 7.33 to ⇒ 7.67.

Answers:

⇒ 7.33:0.27 to 0.39

⇒ 7.67:0.27 to 0.39

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

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

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.

4.12

0.01

0.20

20.5

The margin of error for a 95% confidence level will be ✔ greater than 0.3.less than 0.3.equal to 0.3.

✔ greater than 0.3.

less than 0.3.

equal to 0.3.

What is the margin of error, assuming a 90% confidence level? Round your answer to the nearest tenth.

Answer:

2.6

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 confidence interval is to .

Answers:

Blank 1:0.27 to 0.39

Blank 2:0.27 to 0.39

The margin of error, assuming a 95% confidence level, is approximately . Round to the nearest hundredth

Answer:

0.04

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.

Answer:

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.

Which of the following did you include in your explanation?

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.

Which statement best explains these results?

The population mean changes with each sample.

Random samples vary, and most intervals contain the true mean.

All students debug between 3.4 and 4.7 hours.

The samples were not randomly selected.

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