Data Science Statistical Concepts and Inference 3

Question 1

For a strongly right-skewed income distribution, which measure of central tendency best represents a typical value?

Accepted Answer

Median

Answer

Mean

Answer

Mode

Answer

Range

Question 2

A correlation coefficient of -0.9 indicates:

Accepted Answer

A strong negative linear relationship

Answer

A weak negative relationship

Answer

No relationship

Answer

A strong positive relationship

Question 3

Which statement about correlation and causation is correct?

Accepted Answer

Correlation can arise from a confounding variable without direct causation

Answer

Correlation implies causation

Answer

A high correlation proves one variable causes the other

Answer

Causation requires zero correlation

Question 4

In a normal distribution, approximately what percentage of values fall within two standard deviations of the mean?

Accepted Answer

95%

Answer

68%

Answer

99.7%

Answer

50%

Question 5

A z-score of 0 means the observation is:

Accepted Answer

Exactly at the mean

Answer

Two standard deviations above the mean

Answer

An outlier

Answer

Below the median

Question 6

Which sampling method gives every member of the population an equal chance of selection?

Accepted Answer

Simple random sampling

Answer

Convenience sampling

Answer

Snowball sampling

Answer

Quota sampling

Question 7

The interquartile range (IQR) measures:

Accepted Answer

The spread of the middle 50% of the data

Answer

The difference between the maximum and minimum

Answer

The average distance from the mean

Answer

The most frequent value