Data Science Statistical Concepts and Analysis 2

Question 1

A dataset of household incomes has a few extreme high values. Which measure of central tendency is LEAST affected by these outliers?

Accepted Answer

Median

Answer

Mean

Answer

Range

Answer

Standard deviation

Question 2

A p-value of 0.03 in a test with significance level 0.05 means:

Accepted Answer

Reject the null hypothesis

Answer

Fail to reject the null hypothesis

Answer

The null hypothesis is true

Answer

The effect size is large

Question 3

Which statement best describes the Central Limit Theorem?

Accepted Answer

The sampling distribution of the mean approaches normality as sample size grows

Answer

All data become normal with enough samples

Answer

Variance shrinks to zero with large samples

Answer

The population mean equals the sample mean exactly

Question 4

A correlation coefficient of -0.85 between two variables indicates:

Accepted Answer

A strong negative linear relationship

Answer

A weak negative relationship

Answer

No relationship

Answer

A strong positive relationship

Question 5

What does a 95% confidence interval for a mean actually represent?

Accepted Answer

A range that would contain the true mean in 95% of repeated samples

Answer

A 95% probability the sample mean is correct

Answer

95% of the data fall within the interval

Answer

The mean is exactly in the center 95% of the time

Question 6

Which type of error occurs when you reject a null hypothesis that is actually true?

Accepted Answer

Type I error

Answer

Type II error

Answer

Sampling error

Answer

Measurement error

Question 7

A distribution with a long tail extending to the right is described as:

Accepted Answer

Right-skewed (positively skewed)

Answer

Left-skewed (negatively skewed)

Answer

Symmetric

Answer

Bimodal