Question 1

Which of the following best describes a parameter in statistics?

Accepted Answer

A numerical summary about a population.

Question 2

A researcher wants to study the effect of a new medication on blood pressure. She randomly assigns subjects to either receive the medication or a placebo. What type of study is this?

Accepted Answer

Designed Experiment

Question 3

Which level of measurement is appropriate for ranking students by their final exam scores?

Accepted Answer

Interval

Question 4

Given the following data set: 10, 12, 14, 16, 18, what is the mean?

Accepted Answer

$$\frac{10+12+14+16+18}{5} = 14$$

Question 5

A survey asks people to state their favorite color. What type of data is this?

Accepted Answer

Qualitative/Categorical

Question 6

Which sampling method is most likely to introduce bias if used to select participants for a study?

Accepted Answer

Convenience Sampling

Question 7

A frequency distribution table shows that 45 out of 150 students prefer online classes. What is the relative frequency of students who prefer online classes?

Accepted Answer

$$\frac{45}{150} = 0.3$$

Question 8

Which of the following is NOT a property of the mean?

Accepted Answer

It is resistant to outliers.

Question 9

A histogram is constructed for a data set with the following class boundaries: 10-20, 20-30, 30-40, 40-50. If the frequency for the 30-40 class is 8, what does this mean?

Accepted Answer

There are 8 data values between 30 and 40.

Question 10

Which formula is used to find the position of the 25th percentile in a data set with $$n$$ values?

Accepted Answer

$$\frac{25}{100}(n+1)$$

Question 11

If a data set has a mean of 50 and a standard deviation of 5, what is the z-score for a value of 60?

Accepted Answer

$$z = \frac{60-50}{5} = 2$$

Question 12

Which of the following best describes a confounding variable?

Accepted Answer

A variable that is related to both the explanatory and response variables.

Question 13

A boxplot shows that the right whisker is much longer than the left whisker. What does this indicate about the distribution?

Accepted Answer

The distribution is right-skewed.

Question 14

Which rule states that approximately 95% of data values lie within 2 standard deviations of the mean in a normal distribution?

Accepted Answer

Empirical Rule

Question 15

A time series plot is most useful for showing which of the following?

Accepted Answer

Trends over time

Question 16

If $$P(A) = 0.3$$ and $$P(B) = 0.5$$, and A and B are disjoint events, what is $$P(A \cup B)$$?

Accepted Answer

$$P(A \cup B) = 0.3 + 0.5 = 0.8$$

Question 17

Which of the following is a misleading graph technique?

Accepted Answer

Using inconsistent scales on axes

Question 18

A researcher divides a population into groups based on age and then randomly selects members from each group. What sampling method is this?

Accepted Answer

Stratified Sampling

Question 19

Which measure of dispersion is calculated as the square root of the variance?

Accepted Answer

Standard deviation

Question 20

If the interquartile range (IQR) for a data set is 12 and $$Q_1 = 18$, what is the upper fence for detecting outliers?

Accepted Answer

$$Q_3 + 1.5$$ 	imes IQR$$

Statistics Fundamentals: Concepts, Data, and Summarization

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