Question 1

A pharmaceutical company wants to test the effectiveness of a new drug. They randomly assign patients to receive either the drug or a placebo. Which term best describes this type of study design?

Accepted Answer

Double-blind experiment

Question 2

Which of the following is NOT a measure of center for a data set?

Accepted Answer

Range

Question 3

A researcher collects the heights of 100 students and displays the data using a histogram. What type of variable is being represented?

Accepted Answer

Continuous quantitative variable

Question 4

Given the following data set: 2, 4, 4, 6, 8. What is the median?

Accepted Answer

$$6$$

Question 5

Which formula correctly calculates the sample standard deviation $$s$$ for a data set $$x_1$$, $$x_2$$, ..., x_n$$ with mean $$\overline{x}$$?

Accepted Answer

$$s = \sqrt{\frac{1}{n-1} \sum_{i=1}^{n} (x_i - \overline{x})^2$}$$

Question 6

A frequency distribution table shows the number of cars sold by a dealership each day for a month. Which graphical tool is most appropriate to display this data?

Accepted Answer

Histogram

Question 7

A sample of exam scores has a mean of $$75$$ and a standard deviation of $$10. $$What is the z-score for a student who scored $$95$$?

Accepted Answer

$$z = 2$$

Question 8

Which of the following statements about correlation is TRUE?

Accepted Answer

Correlation measures the strength and direction of a linear relationship between two variables.

Question 9

A scatterplot of hours studied and exam scores shows a positive linear trend. Which statistical tool would best quantify this relationship?

Accepted Answer

Pearson correlation coefficient

Question 10

Which formula represents the least-squares regression line for predicting $$y$$ from $$x$$?

Accepted Answer

$$y = a + bx$$

Question 11

A data set has a mean of $$50$$, a median of $$45$$, and a mode of $$40. $$Which statement best describes the distribution?

Accepted Answer

The distribution is right-skewed.

Question 12

A hospital wants to compare the recovery times of patients who received two different treatments. Which statistical method is most appropriate to analyze the relationship between treatment type and recovery time?

Accepted Answer

Scatterplot and correlation analysis

Question 13

Which of the following is a poor sampling design that can lead to biased results?

Accepted Answer

Convenience sampling

Question 14

A boxplot is used to display which of the following characteristics of a data set?

Accepted Answer

Shape, center, spread, and outliers

Question 15

If the Pearson correlation coefficient $$r$$ between two variables is $$-0.85$$, what does this indicate?

Accepted Answer

A strong negative linear relationship

Question 16

A researcher finds that the least-squares regression line for predicting cholesterol level ($$y) $$from age ($$x) is$$ $$y = 120 + 2x. $$What is the predicted cholesterol level for a 40-year-old?

Accepted Answer

$$y = 200$$

Question 17

Which of the following is NOT a characteristic used to describe a frequency distribution?

Accepted Answer

Sample size

Question 18

A data set has values: 10, 15, 20, 25, 30. What is the range?

Accepted Answer

$$20$$

Question 19

Which of the following best describes an outlier in a data set?

Accepted Answer

A value that is much higher or lower than most other values

Question 20

In a study examining the relationship between exercise frequency and blood pressure, which variable is most likely the response (dependent) variable?

Accepted Answer

Blood pressure

Fundamental Concepts in Statistics: Sampling, Distributions, Measures, and Regression

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