Q: A study in a statistics class with $$N = 120$$ students asks each student to take a test and records their scores. The frequency distribution shows the data that were collected. If 20 students scored between 80 and 89, what percentage of students scored in this range?

$$\frac{20}{120} \times 100 = 16.67\%$$

Question 1

Which of the following best describes an observational study?

Accepted Answer

A study where researchers observe subjects and measure variables of interest without assigning treatments.

Question 2

A survey of high school seniors reported that 81% of those sampled are interested in pursuing a college education. This is an example of:

Accepted Answer

Descriptive statistics

Question 3

Parking at a large university has become a very big problem. University administrators are interested in estimating the percentage of students who park in unauthorized areas. They randomly select 200 students from a list of all students and ask them if they have ever parked in an unauthorized area. This is an example of:

Accepted Answer

Inferential statistics

Question 4

A researcher is interested in estimating the average percentage of cardiologists who have been sued for malpractice. She randomly selects 100 cardiologists from a national directory and asks them if they have ever been sued. The population in this study is:

Accepted Answer

All cardiologists in the national directory

Question 5

Which of the following statements about samples and populations is TRUE?

Accepted Answer

A sample is a subset of a population.

Question 6

A study is conducted to determine the average number of hours students at a university spend studying per week. The researchers randomly select 50 students and record their study hours. The sample in this study is:

Accepted Answer

The 50 students selected

Question 7

Which of the following is an example of inferential statistics?

Accepted Answer

Estimating the proportion of all students at a university who own a car based on a sample.

Question 8

A study finds that 60% of a sample of 200 students at a university own a laptop. Which of the following best describes the parameter and statistic in this scenario?

Accepted Answer

Parameter: All students at the university, Statistic: 60%

Question 9

A researcher wants to estimate the average number of hours per week that nurses work in a hospital. She randomly selects 30 nurses and records their hours. Which of the following is the population?

Accepted Answer

All nurses in the hospital

Question 10

A study in a statistics class with $$N = 120$$ students asks each student to take a test and records their scores. The frequency distribution shows the data that were collected. If 20 students scored between 80 and 89, what percentage of students scored in this range?

Accepted Answer

$$\frac{20}{120} 	imes 100 = 16.67\%$$

Question 11

Which of the following is a right-skewed distribution?

Accepted Answer

A distribution where the mean is greater than the median.

Question 12

The amount of time workers spend coordinating with each other each week is shown to have a strong normal distribution with mean $$\mu = 15$$ hours and standard deviation $$\sigma = 2$$ hours. What percentage of workers spend between 13 and 17 hours coordinating?

Accepted Answer

About 68\%

Question 13

If a distribution is symmetric and bell-shaped, which of the following statements is TRUE?

Accepted Answer

The mean, median, and mode are all equal.

Question 14

A researcher collects data on the number of packages delivered by the United States Postal Service in a day. Which type of variable is this?

Accepted Answer

Discrete variable

Question 15

Which of the following is an example of a continuous variable?

Accepted Answer

The height of students in a classroom.

Question 16

A study finds that the average salary of employees at a company is $$\50$$,000$$ with a standard deviation of $$\$$5,000. If $$the salaries are normally distributed, what percentage of employees earn between $$\45$$,000$$ and $$\$$55,000$$?

Accepted Answer

About 68\%

Question 17

Which of the following best describes the difference between descriptive and inferential statistics?

Accepted Answer

Descriptive statistics summarize data, while inferential statistics make generalizations about a population.

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