Lecture 24 ʚɞ ⁺˖ ⸝⸝

Question 1

What are the two types of distributions discussed?

Answer 1

Univariate and Bivariate

Univariate describes a single variable, while Bivariate describes the relationship between two variables.

Question 2

In a Univariate distribution, what is plotted on the y-axis?

Answer 2

Frequency or probability

This represents how often different values of the variable occur.

Question 3

What are the three characteristics used to describe a Univariate distribution?

Answer 3

Shape, Center, Spread

These characteristics help summarize the distribution of a single variable.

Question 4

What are the three characteristics used to describe a Bivariate distribution?

Answer 4

Form, Direction, Strength

These characteristics help summarize the relationship between two different variables.

Question 5

What is the purpose of whiskers in a box and whisker plot?

Answer 5

To capture the data outside of the box

Whiskers extend to a limit defined by 1.5 x IQR.

Question 6

What is labeled as a ‘suspected outlier’ in a box and whisker plot?

Answer 6

Any observation lying beyond the whiskers

These observations are marked with a dot.

Question 7

List the four sampling methods mentioned.

Answer 7

• Simple Random Sample
• Cluster Sample
• Stratified Random Sample
• Systematic Sample

These methods are used to gather data in a representative manner.

Question 8

What is essential for a sampling methodology to be effective?

Answer 8

It should be representative (random and independent)

This ensures that the sample accurately reflects the population.

Question 9

What are the two probability rules mentioned?

Answer 9

• General Addition Rule
• General Multiplication Rule

These rules help calculate probabilities in different scenarios.

Question 10

What theorem is used to calculate conditional probabilities?

Answer 10

Bayes’ Theorem

This theorem relates the conditional and marginal probabilities of random events.

Question 11

What is the focus of HW4 in the context of statistics?

Answer 11

Sample Proportions and T tests

T tests are used to determine if there are significant differences between group means.

Question 12

What statistical method is introduced in HW7?

Answer 12

Ordinary Least Squares

This method is used in regression analysis to minimize the sum of squared differences.

Question 13

What is a potential issue in regression analysis mentioned?

Answer 13

Omitted Variable Bias

This occurs when a model leaves out one or more relevant variables.

Question 14

What type of variables are discussed in the context of regression?

Answer 14

Categorical Variables

These are variables that can take on one of a limited, and usually fixed, number of possible values.

Question 15

True or False: Correlation implies causation.

Answer 15

False

Correlation does not imply that one event causes the other.

Question 16

Fill in the blank: The frequent consumption of fried potatoes is associated with an increased _______.

Answer 16

mortality risk

This statement highlights a correlation that warrants further investigation.

Question 17

What is the significance of the ‘Octopus predicting the world cup winner’ example?

Answer 17

It demonstrates bias in sampling

This example illustrates how predictions can be influenced by non-random factors.

Question 18

What is the focus of HW8?

Answer 18

Test 2 Makeup and Final Writeup

This indicates a review and summary phase in the coursework.