DA Statistical Analysis

Question 1

What does a p-value less than 0.05 typically indicate in hypothesis testing?

Accepted Answer

The result is statistically significant

Answer

A p-value below 0.05 means there is less than a 5% probability the observed result occurred by chance, so we reject the null hypothesis.

Question 2

Which measure of central tendency is most affected by extreme outliers?

Accepted Answer

Mean

Answer

The mean sums all values and divides by count, so extreme outliers pull it significantly in their direction.

Question 3

What is the standard deviation a measure of?

Accepted Answer

Spread or dispersion around the mean

Answer

Standard deviation quantifies how much individual data points deviate from the mean on average.

Question 4

A data analyst runs a t-test. What is the primary purpose of this test?

Accepted Answer

Compare means of two groups

Answer

A t-test is used to determine whether there is a statistically significant difference between the means of two groups.

Question 5

What does a correlation coefficient of -0.9 indicate?

Accepted Answer

Strong negative relationship

Answer

A correlation of -0.9 is close to -1, indicating a strong inverse relationship where one variable increases as the other decreases.

DA - Data Analyst Practice Test