Q: Which of the following is the correct formula for the coefficient of variation (CV) for a sample?

$$CV = \frac{s}{\overline{x}} \times 100\%$$

Question 1

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

Accepted Answer

Descriptive statistics involve organizing, summarizing, and displaying data, while inferential statistics involve making predictions or inferences about a population based on a sample.

Question 2

A researcher collects the heights (in cm) of 100 adults. Which type of variable is height in this context?

Accepted Answer

Quantitative, continuous

Question 3

Given the following data set: 2, 4, 4, 6, 8, 10, 12. What is the median?

Accepted Answer

$$6$$

Question 4

Which measure of central tendency is most affected by outliers?

Accepted Answer

Mean

Question 5

A distribution is said to be skewed right (positively skewed) if:

Accepted Answer

The mean is greater than the median

Question 6

Calculate the range for the following data set: 7, 12, 15, 20, 25.

Accepted Answer

$$18$$

Question 7

Which formula correctly represents the sample standard deviation?

Accepted Answer

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

Question 8

A sample of five exam scores is: 60, 70, 80, 90, 100. What is the mean?

Accepted Answer

$$80$$

Question 9

Which of the following is NOT a measure of central tendency?

Accepted Answer

Range

Question 10

A box-and-whisker plot is constructed using which summary statistics?

Accepted Answer

Minimum, Q1, median, Q3, maximum

Question 11

Given a data set with Q1 = 20, Q3 = 40, what is the interquartile range (IQR)?

Accepted Answer

$$20$$

Question 12

Which of the following is the correct formula for the coefficient of variation (CV) for a sample?

Accepted Answer

$$CV = \frac{s}{\overline{x}} 	imes 100\%$$

Question 13

A researcher finds that the mean income in a sample is much higher than the median. What does this suggest about the distribution of incomes?

Accepted Answer

The distribution is skewed right (positively skewed)

Question 14

Which of the following statements about the median is TRUE?

Accepted Answer

The median divides the data set into two equal halves

Question 15

If a data set has the following five-number summary: min = 10, Q1 = 20, median = 30, Q3 = 40, max = 100, which value is a potential outlier according to the 1.5*IQR rule?

Accepted Answer

100

Question 16

Which of the following best describes a uniform distribution?

Accepted Answer

All frequencies are equal across the range of values

Question 17

A sample of 10 students has GPAs: 1.90, 3.00, 2.53, 3.71, 2.12, 1.76, 2.71, 1.39, 4.00, 3.33. What is the median GPA?

Accepted Answer

$$2.62$$

Question 18

Which of the following is a correct interpretation of a standard deviation of zero in a data set?

Accepted Answer

All data values are equal to the mean

Question 19

Which of the following is a discrete variable?

Accepted Answer

The number of children in a family

Question 20

If the sum of squared deviations from the mean for a sample of size $$n = 5 is$$ $$20$$, what is the sample variance?

Accepted Answer

$$5$$

Descriptive Statistics: Data Classification, Central Tendency, Dispersion, and Position

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