Question 1

In a study to determine the mean age of all employees at Capital One Financial Corporation, which of the following best describes the population?

Accepted Answer

All employees working at Capital One Financial Corporation

Question 2

Which of the following is a parameter, not a statistic?

Accepted Answer

$$\mu ($$the mean of the population)

Question 3

A real estate company wants to estimate the proportion of all properties it sold for $500,000 or more. Which symbol represents the parameter of interest?

Accepted Answer

$$p ($$read pi)

Question 4

Suppose a university wants to estimate the mean height of all its students. Which of the following is the best example of a sample statistic in this context?

Accepted Answer

$$\bar{X} = 68.5$$ inches, the mean height of 150 sampled students

Question 5

Which of the following statements is a statistical hypothesis?

Accepted Answer

$$\mu = 32.4$$ years, the conjectured mean age of all employees at Capital One Financial Corporation

Question 6

A researcher wants to estimate the correlation between years enrolled in a 401(k) plan and the total value of the plan for all U.S. employees with 401(k) plans. What is the parameter of interest?

Accepted Answer

$$\rho ($$read rho), the correlation in the population

Question 7

Which of the following best describes a sample in the context of estimating the mean number of people attending Division I athletic competitions?

Accepted Answer

A group of $$n = 200$$ Division I athletic competitions selected to include a wide range of sports

Question 8

Which of the following is a correct example of a statistical inference?

Accepted Answer

Based on a sample of 100 employees, we estimate that the mean age of all employees at Capital One Financial Corporation is 38.4 years.

Question 9

If $$25$$ out of $$250$$ sampled properties sold by Century 21 Real Estate LLC had a selling price of $$500,000 or $$more, what is the value of the sample proportion $$\hat{p}$$?

Accepted Answer

$$\hat{p} = \frac{25}{250} = 0.10$$

Question 10

Which of the following symbols is used to denote the standard deviation of a sample?

Accepted Answer

$$s$$

Question 11

A film studio wants to estimate the proportion of all people who watched a movie and enjoyed it. Which of the following is the best approach to estimate this proportion?

Accepted Answer

Select a sample of $$n = 500$$ people who watched the movie, ask if they enjoyed it, and compute $$\hat{p}$$, the sample proportion who enjoyed it.

Question 12

Which of the following best describes the difference between a parameter and a statistic?

Accepted Answer

A parameter describes a characteristic of a population, while a statistic describes a characteristic of a sample.

Question 13

Which of the following is the correct symbol for the variance of a population?

Accepted Answer

$$\$$sigma^2$$

Question 14

A researcher wants to test the hypothesis that the mean number of people attending Division I athletic competitions is 1,725. Which of the following is the correct way to test this hypothesis?

Accepted Answer

Select a sample of Division I competitions, compute the sample mean $$\bar{X}$$, and use it to test if $$\mu = 1725 is $$reasonable.

Question 15

Which of the following is NOT a correct pairing of a parameter and its corresponding statistic?

Accepted Answer

$$\rho ($$population correlation) and $$\mu ($$sample mean)

Question 16

Which of the following best describes a statistical test?

Accepted Answer

A procedure where a hypothesis about a population parameter is tested using statistics computed from sample data.

Question 17

Suppose you want to estimate the mean height of all students at a university, but the university does not record this information. What is the best approach?

Accepted Answer

Select a representative sample of students, measure their heights, and use the sample mean $$\bar{X} to $$estimate the population mean $$\mu.$$

Question 18

Which of the following is the correct symbol for the sample size?

Accepted Answer

$$n$$

Question 19

A sample of 150 students at a university has a mean height of 68.5 inches. Which of the following is a correct statistical inference?

Accepted Answer

We estimate that the mean height of all students at this university is 68.5 inches.

Introduction to Statistics: Populations, Parameters, Samples, and Inference

Guida di studio - Domande di pratica

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