Q: Given the following grades and their weights: A (4 points, 2 classes), B (3 points, 1 class), C (2 points, 1 class), what is the weighted mean (GPA)?

$$\displaystyle \frac{(4 \times 2) + (3 \times 1) + (2 \times 1)}{2+1+1} = \frac{8+3+2}{4} = 3.25$$

Question 1

Which of the following best describes the mean of a data set?

Accepted Answer

The sum of all data entries divided by the number of entries: $$\displaystyle \bar{x} = \frac{\sum x}{n}$$

Question 2

A sample of weights (in pounds) is: 274, 235, 223, 268, 290, 285, 235. What is the median weight?

Accepted Answer

268 pounds

Question 3

Which measure of central tendency is most affected by outliers?

Accepted Answer

Mean

Question 4

Given the following grades and their weights: A (4 points, 2 classes), B (3 points, 1 class), C (2 points, 1 class), what is the weighted mean (GPA)?

Accepted Answer

$$\displaystyle \frac{(4 	imes 2) + (3 	imes 1) + (2 	imes 1)}{2+1+1} = \frac{8+3+2}{4} = 3.25$$

Question 5

A distribution is described as 'skewed right.' Which of the following is true about the relationship between mean, median, and mode?

Accepted Answer

Mean \u003e Median \u003e Mode

Question 6

Which of the following is the formula for estimating the mean of grouped data using a frequency distribution?

Accepted Answer

$$\displaystyle \bar{x} = \frac{\sum f x}{n}$$, where $$x is $$the midpoint and $$f is $$the frequency

Question 7

If a data set has two entries that occur with the same greatest frequency, what is the mode?

Accepted Answer

The data set is bimodal.

Question 8

A frequency distribution of cell phone screen times (in minutes) for 30 adults is used to estimate the mean screen time. Why is this estimate not exact?

Accepted Answer

Because the estimate uses class midpoints instead of actual data values.

Question 9

Which of the following best describes a uniform distribution?

Accepted Answer

All entries or classes have equal or approximately equal frequencies.

Question 10

A data set is: 10, 12, 12, 15, 18, 20, 65. Which measure of central tendency best describes a typical entry, and why?

Accepted Answer

The median, because the mean is influenced by the outlier 65.

Question 11

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

Accepted Answer

Range

Question 12

In a symmetric distribution, which of the following is true?

Accepted Answer

Mean = Median = Mode

Question 13

A researcher collects the following data: 5, 7, 7, 8, 10. What is the mode?

Accepted Answer

7

Question 14

Which scenario best illustrates the use of a weighted mean?

Accepted Answer

Calculating a student's GPA where each course has a different credit value.

Question 15

If a data set is skewed left, which of the following is the correct order of mean, median, and mode?

Accepted Answer

Mean \u003c Median \u003c Mode

Question 16

A sample of exam scores is: 70, 75, 80, 85, 90, 95. What is the median score?

Accepted Answer

82.5

Question 17

Which of the following is a disadvantage of using the mean as a measure of central tendency?

Accepted Answer

It is greatly affected by outliers.

Descriptive Statistics: Measures of Central Tendency

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