Data Science Analysis 2

Question 1

A dataset of household incomes has a mean far higher than its median. What does this indicate?

Accepted Answer

Right (positive) skew

Answer

Left (negative) skew

Answer

A perfectly symmetric distribution

Answer

No variance in the data

Question 2

Which measure of central tendency is most robust to outliers?

Accepted Answer

Median

Answer

Mean

Answer

Standard deviation

Answer

Range

Question 3

You compute the interquartile range (IQR) to detect outliers. Which boundary commonly flags an outlier?

Accepted Answer

Below Q1 - 1.5*IQR or above Q3 + 1.5*IQR

Answer

Below the mean - 1 SD

Answer

Any value above the median

Answer

Below Q1 only

Question 4

A correlation coefficient between two variables is -0.9. What does this describe?

Accepted Answer

A strong negative linear relationship

Answer

A weak negative relationship

Answer

No relationship

Answer

A strong positive relationship

Question 5

Which statement about correlation and causation is correct?

Accepted Answer

Correlation does not imply causation

Answer

Correlation always implies causation

Answer

A high correlation proves one variable causes the other

Answer

Causation requires zero correlation

Question 6

When summarizing a categorical variable, which is most appropriate?

Accepted Answer

Frequency counts or proportions

Answer

Mean and standard deviation

Answer

Median and IQR

Answer

A correlation matrix

Question 7

A boxplot shows the box much wider on the upper half than the lower half. This suggests the data is:

Accepted Answer

Skewed toward higher values

Answer

Perfectly symmetric

Answer

Free of any spread

Answer

Bimodal by definition