Q: In a study comparing support for Party A in two regions over two years, which of the following is a correct way to calculate the percentage change in support in the East region from 2007 to 2008?

$$\frac{V_{2008} - V_{2007}}{V_{2007}} \times 100$$

Question 1

Which of the following best describes the variable 'level of support for corporate sustainability' as used in a survey of 592 senior managers?

Accepted Answer

It is a quantitative variable because it measures a numerical value.

Question 2

A study investigates the incidence of difficult bag-mask ventilation (DBMV) in children undergoing surgery. Which of the following is the population of interest?

Accepted Answer

All children undergoing elective surgery requiring bag-mask ventilation.

Question 3

In a study of mountain bikers, which variable is most likely to be classified as quantitative?

Accepted Answer

Number of years doing mountain bike riding

Question 4

Given the following data for the ages of 50 women: minimum = 25, maximum = 65, what is the range?

Accepted Answer

$$65 - 25 = 40$$

Question 5

A histogram of exam grades is strongly skewed to the left. Which measure of central tendency is most likely to be affected by this skewness?

Accepted Answer

The mean

Question 6

In a study comparing support for Party A in two regions over two years, which of the following is a correct way to calculate the percentage change in support in the East region from 2007 to 2008?

Accepted Answer

$$\frac{V_{2008} - V_{2007}}{V_{2007}} 	imes 100$$

Question 7

Which of the following best describes an observational study?

Accepted Answer

Researchers observe subjects without manipulating variables.

Question 8

A bar graph shows the number of oil spills by cause. If 'Groundings' has the highest bar, what can you infer?

Accepted Answer

Groundings are the most common cause of oil spills.

Question 9

Given the formula for sample variance $$s^2$$ = \frac{\sum_{i=1}^n (x_i - \bar{x}$$)^2$$}{n-1}$$, what does n$ represent?

Accepted Answer

The number of observations in the sample.

Question 10

If the smallest value in a data set is omitted, what happens to the standard deviation?

Accepted Answer

It will decrease.

Question 11

A study of plant cover in two regions finds the mean for the Gold Desert region is $$\bar{x} = 28. If $$the median is also 28, what does this suggest about the distribution?

Accepted Answer

The distribution is likely symmetric.

Question 12

In a study of headgear use in youth soccer, which variable is most likely to be considered categorical?

Accepted Answer

Type of headgear worn (yes/no)

Question 13

Which formula would you use to calculate the mean of a data set with $$n$$ values $$x_1$$, $$x_2$$, ..., x_n$$?

Accepted Answer

$$\bar{x} = \frac{\sum_{i=1}^n x_i}{n}$$

Question 14

A frequency histogram of exam grades shows a large number of grades between 120 and 130. What does this indicate about the distribution?

Accepted Answer

The distribution is skewed to the left.

Question 15

Which of the following is a correct interpretation of the median in a data set?

Accepted Answer

It is the middle value when the data are arranged in order.

Question 16

In a study, the sample mean is found to be 122.3 and the sample median is 125. What does this suggest about the data?

Accepted Answer

The data are skewed to the left.

Question 17

Which of the following is a real-world example of a quantitative variable?

Accepted Answer

Number of years of mountain biking experience

Question 18

If the mean and median of a data set are equal, which of the following is most likely true?

Accepted Answer

The data set is symmetric.

Question 19

Which of the following best describes the standard deviation?

Accepted Answer

It is the square root of the variance.

Question 20

A study finds that the sample mean is affected by extreme values, but the median is not. What does this imply?

Accepted Answer

The median is a robust measure of central tendency.

Key Concepts and Applications in Descriptive Statistics and Data Analysis

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