数据分析习题1(1)

Identify the shape of a distribution as symmetric, right skewed, or left skewed, and unimodal, bimodoal, multimodal, or uniform.

Question 9

Two distributions (A and B) are shown on the box plot below. Which of the following statements is not supported by the plot?

Your Answer Score Exp

Both distributions are unimodal.

Median of A is higher than median of B.

B is more variable than A.

Both distributions are roughly symmetric. Inorrect 0.00 Both

Total 0.00 / 1.00

Question ExplanationThis question refers to the following learning objective(s):

Use histograms and box plots to visualize the shape, center, and spread of numerical distributions, and intensity maps for visualizing the spatial distribution of the data.

Question 10

A recent housing survey was conducted to determine the price of a typical home in a city that is mostly middle-class, with one very expensive suburb. The mean price of a house in this city is roughly $650,000. Which of the following statements is most likely to be true?

Your Answer Score Explanation

We need to know the standard deviation question

to

answer

this

There are about as many houses in this city that cost more than $650,000 than less than this amount.

Majority of houses in this city cost more than $650,000.

Majority of houses in this city Correct 1.00 cost less than $650,000.

Since the city is mostly middle-class, with one

expect the distribution to be right skewed, and

than the median. Since 50% of observations fa

observations (i.e. majority) will cost less than $

Total 1.00 / 1.00

Question ExplanationThis question refers to the following learning objective:

Define a robust statistic (e.g. median, IQR) as a statistics that is not heavily affected by skewness and extreme outliers, and determine when such statistics are more appropriate measures of center and spread compared to other similar statistics.

Question 11

It is relatively common for fish to be mislabeled in supermarkets and even in restaurants. The table below shows the results of a study where a random sample of 156 fish for sale were collected and genetically tested. The researchers classified each sample as being labeled properly or being mislabeled. What fraction of smoked fish in the sample were mislabeled? Choose the closest answer.

Your Answer Score Explanation

28%

9%

72% Inorrect 0.00 Look among only the smoked fish, and find the proport

18%

78%

Total 0.00 / 1.00

Question ExplanationThis question refers to the following learning objective(s):

Use contingency tables and segmented bar plots or mosaic plots to assess the relationship between two categorical variables.

Question 12

Does meditation cure insomnia? Researchers randomly divided 400 people into two equal- sized groups. One group meditated daily for 30 minutes, the other group attended a 2-hour information session on insomnia. At the beginning of the