Question 1

Which of the following is the best graphical display for showing the distribution of a quantitative variable such as monthly average stock prices?

Accepted Answer

Histogram

Question 2

A distribution of exam scores is unimodal and symmetric. Which measures of center and spread are most appropriate to summarize this data?

Accepted Answer

Mean and standard deviation

Question 3

Given the data set: 21, 22, 24, 33, 33, 36, 38, 41, what would the stem-and-leaf display look like for the 30s?

Accepted Answer

3 | 3 3 6 8

Question 4

Which of the following statements about outliers is TRUE?

Accepted Answer

Outliers can affect statistical methods and may be the most informative part of the data.

Question 5

A distribution is described as 'skewed to the right.' Which of the following best describes its shape?

Accepted Answer

The right tail is longer than the left tail.

Question 6

Calculate the z-score for a house price of $$340,000, given a mean of 175$$,000 and a standard deviation of $55,000.

Accepted Answer

$$z = \frac{340,000 - 175,000}{55,000} = 3.00$$

Question 7

Which of the following is NOT a component of the five-number summary?

Accepted Answer

Mean

Question 8

If a distribution is strongly skewed to the right, which transformation is most likely to make it more symmetric?

Accepted Answer

Taking the logarithm of the data

Question 9

A boxplot displays which of the following features of a distribution?

Accepted Answer

The quartiles, median, and possible outliers

Question 10

Which of the following is the formula for the interquartile range (IQR)?

Accepted Answer

$$IQR = Q_3$ - Q_1$

Question 11

A time series plot is most useful for which type of data?

Accepted Answer

Data collected over time

Question 12

Which of the following is TRUE about the standard deviation?

Accepted Answer

It is appropriate for symmetric distributions.

Question 13

If a distribution has multiple modes, what should you consider doing?

Accepted Answer

Try to separate the data into groups.

Question 14

Which of the following is the correct formula for the sample mean $$\bar{x} of$$ $$n$$ values $$x_1$$, $$x_2$$, ..., x_n$$?

Accepted Answer

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

Question 15

Which of the following is a reason to standardize a variable (calculate z-scores)?

Accepted Answer

To compare values measured on different scales

Question 16

A boxplot shows a long whisker on the left and several low outliers. What can you conclude about the distribution?

Accepted Answer

It is skewed to the left

Question 17

Which of the following is NOT an appropriate use of a histogram?

Accepted Answer

Displaying the distribution of a categorical variable

Question 18

If the mean and median of a distribution are very different, what does this suggest about the distribution?

Accepted Answer

The distribution is likely skewed.

Question 19

Which of the following best describes the effect of an extreme outlier on the mean and median?

Accepted Answer

The mean is more affected than the median.

Question 20

A real estate analyst finds that the average house price is $$175,000 with a standard deviation of 55$$,000. What is the z-score for a house that costs $500,000?

Accepted Answer

$$z = \frac{500,000 - 175,000}{55,000} = 5.91$$

Displaying and Describing Quantitative Data: Study Notes

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드