Question 1

A survey found that 72% of all students use the campus gym. A random sample of 120 students was taken, and 78% reported using the gym. Which of the following best describes the 'statistic' in this context?

Accepted Answer

The percentage of students in the sample who use the campus gym.

Question 2

Which of the following variables is both quantitative and measured at the ratio level?

Accepted Answer

The number of minutes a student exercises per day.

Question 3

A researcher wants to determine the favorite type of music among all residents of Florida. Which sampling method is most appropriate and why?

Accepted Answer

Simple random sampling, because it gives every resident an equal chance of being selected.

Question 4

Given the following frequency distribution for class sizes at universities:

26–32: 4
32–38: 4
38–44: 7
44–50: 3
50–55: 2

What is the class width?

Accepted Answer

$$6$$

Question 5

For the class interval 38–44, what is the class midpoint?

Accepted Answer

$$41$$

Question 6

If the total number of data points is 20, what is the relative frequency for the class 32–38 (with frequency 4)?

Accepted Answer

$$0.20$$

Question 7

A pain level rated on a scale from 1 to 10 is an example of which type of variable and level of measurement?

Accepted Answer

Quantitative; Ordinal

Question 8

The lifespans of laboratory mice are normally distributed with mean $$\mu = 50$$ days and standard deviation $$\sigma = 5$$ days. What is the $$z-$$score for a mouse that lived 60 days?

Accepted Answer

$$z = 2$$

Question 9

A university class has 50 students. 20 are Biology majors, 18 are in the Environmental Club, and 6 are both. What is the probability that a randomly selected student is either a Biology major or a member of the Environmental Club?

Use the formula:

$$P(A \cup B) = P(A) + P(B) - P(A \cap B)$$

Accepted Answer

$$0.64$$

Question 10

Which of the following is an example of a variable measured at the nominal level?

Accepted Answer

Political party affiliation

Question 11

A sample is best defined as:

Accepted Answer

A subset of the population selected for study.

Question 12

Which of the following best describes a parameter?

Accepted Answer

A characteristic or measure obtained by using all the data values from a population.

Question 13

Which of the following is true about the difference between interval and ratio levels of measurement?

Accepted Answer

Ratio level has a true zero, while interval does not.

Question 14

A researcher wants to estimate the average GPA of the 25 students in a small honors seminar class. Which data collection method is most appropriate?

Accepted Answer

Census, because the population is small and accessible.

Question 15

Given the frequency distribution:

26–32: 4
32–38: 4
38–44: 7
44–50: 3
50–55: 2

What is the cumulative frequency up to and including the class 38–44?

Accepted Answer

$$15$$

Question 16

If a mouse lived 45 days, what is its $$z-$$score given $$\mu = 50$$ and $$\sigma = 5$$?

Accepted Answer

$$z = -1$$

Question 17

Which of the following is a correct interpretation of a $$z-$$score of $$2$$?

Accepted Answer

The value is 2 standard deviations above the mean.

Question 18

Which of the following is an example of a variable measured at the interval level?

Accepted Answer

Temperature in degrees Fahrenheit

Question 19

In a frequency distribution, the mode class is:

Accepted Answer

The class with the highest frequency.

Question 20

If a variable is qualitative and its categories have a meaningful order, what is its level of measurement?

Accepted Answer

Ordinal

STA2014-0001 Practice Exam 1: Step-by-Step Statistics Guidance

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