Question 10

Use the following information for Questions 10-19

The World Bank collects information on the GDP of various nations and publishes it on their website online. Fifty countries are randomly selected; their mean GDP is $39.5 billion. We assume that the population standard deviation for the GDP variable is $12.3 billion.

What procedure do you use to get the critical value and why?

Group of answer choices

z-interval procedure, because we know the population standard deviation and that the sample size is large

t-interval procedure, because the population standard deviation is not known and the sample size is large

t-interval procedure, because the population standard deviation is known and the sample size is small

z-interval procedure, because we do not know the population standard deviation and the sample size is large

Flag question: Question 11

Use the following information for Questions 10-19

The World Bank collects information on the GDP of various nations and publishes it on their website online. Fifty countries are randomly selected; their mean GDP is $39.5 billion. We assume that the population standard deviation for the GDP variable is $12.3 billion.

Determine the critical value at the 95% confidence level, using a z or a t table as appropriate. Answer in three decimal places

Flag question: Question 12

Use the following information for Questions 10-19

The World Bank collects information on the GDP of various nations and publishes it on their website online. Fifty countries are randomly selected; their mean GDP is $39.5 billion. We assume that the population standard deviation for the GDP variable is $12.3 billion.

Calculate the margin of error at the 95% confidence level. Do not convert the values to billions of dollars (use the numbers 39.5 and 12.3 as they are written) and write the answer in the standard XX.XXX or XXX.XXX format. Answer in three decimal places.

Flag question: Question 13

Use the following information for Questions 10-19

The World Bank collects information on the GDP of various nations and publishes it on their website online. Fifty countries are randomly selected; their mean GDP is $39.5 billion. We assume that the population standard deviation for the GDP variable is $12.3 billion.

What information does the margin of error provide in this context?

Group of answer choices

Margin of error calculates how one population will differ from another population value.

Margin of error provides a range in which one can be 100% certain a calculated parameter falls into.

Margin of error indicates how a population value differs from a sample statistic.

Margin of error indicates how accurate an estimator is for the value of the unknown population parameter.

Flag question: Question 14

Use the following information for Questions 10-19

The World Bank collects information on the GDP of various nations and publishes it on their website online. Fifty countries are randomly selected; their mean GDP is $39.5 billion. We assume that the population standard deviation for the GDP variable is $12.3 billion.

Find the 95% confidence interval for the mean age, , of all countries in the world.Round to three decimal places.

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Flag question: Question 15

Use the following information for Questions 10-19

The World Bank collects information on the GDP of various nations and publishes it on their website online. Fifty countries are randomly selected; their mean GDP is $39.5 billion. We assume that the population standard deviation for the GDP variable is $12.3 billion.

Which sentence below best defines what this confidence interval represents?

Group of answer choices

We are 95% confident that the population GDP for all countries in the world lies +/- 2 standard deviations from the mean, which is proven by the Empirical Rule.

We are 95% confident that the population GDP for all the countries in the world lies between the lower and upper limit found in the previous question.

We are more than 95% confident that the population GDP for all the countries in the world in the world lies between the lower and upper limit found in the previous question.

We are not 95% confident that the population GDP for all countries in the world lies between the lower and upper limit found in the previous question.

Flag question: Question 16

Use the following information for Questions 10-19

The World Bank collects information on the GDP of various nations and publishes it on their website online. Fifty countries are randomly selected; their mean GDP is $39.5 billion. We assume that the population standard deviation for the GDP variable is $12.3 billion.

Now a sample of 100 countries is randomly selected. Assume that the sample mean and population standard deviation remain unchanged. Calculate the new 95% confidence interval. Round to three decimal places.

[ , ]

Flag question: Question 17

Use the following information for Questions 10-19

The World Bank collects information on the GDP of various nations and publishes it on their website online. Fifty countries are randomly selected; their mean GDP is $39.5 billion. We assume that the population standard deviation for the GDP variable is $12.3 billion.

Choose the answer that best explains why this confidence level is different than the previous one you calculated.

Group of answer choices

Increasing the sample size decreases the margin of error and therefore, reduces the width of the confidence interval. We are less accurate on our prediction.

Increasing sample size changes the critical value and increases the margin of error. We are less accurate on our prediction.

Increasing sample size changes the critical value and increases the margin of error. We are more accurate on our prediction.

Increasing the sample size decreases the margin of error and therefore, reduces the width of the confidence interval. We are more accurate on our prediction.

Flag question: Question 18

Use the following information for Questions 10-19

The World Bank collects information on the GDP of various nations and publishes it on their website online. Fifty countries are randomly selected; their mean GDP is $39.5 billion. We assume that the population standard deviation for the GDP variable is $12.3 billion.

Now calculate a 90% confidence interval with the original sample of 100 people.Round to three decimal places.

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Flag question: Question 19

Use the following information for Questions 10-19

The World Bank collects information on the GDP of various nations and publishes it on their website online. Fifty countries are randomly selected; their mean GDP is $39.5 billion. We assume that the population standard deviation for the GDP variable is $12.3 billion.

How does this decrease in confidence level affect the accuracy of the estimation? Choose the correct answer below. NOTE: = decrease and =increase

Group of answer choices

If confidence level , critical value , margin of error , width of interval , and precision .

If confidence level , critical value , margin of error , width of interval , and precision .

If confidence level , critical value , margin of error , width of interval , and precision .

If confidence level , critical value , margin of error , width of interval , and precision .