Intro to data regression

Intro to data regression

By Jesus Molina

​Understanding regression analysis and possible applications.

​Regression Analysis (simple definition):

is the process use to estimate the relationship between a dependent variable and one, or more, Independent variables. ​

​A few applications:

1. ​Monthly sales based on cost of sales and selling expense.

2. Airline and truck company fuel expense based on miles driven and fuel cost per gallon.

3. Maintenance expense based on production levels.

4. Inventory at each location of a retail company based on store sales, store square footage, regional economic data, and type of store location. ​

​Understanding data and lines of best fit.

​Data is represented by individual points on a coordinate plane, AKA scatterplot.

​

​In order to visually determine the possibility of correlation, or relationship, between the variables we use "the line of best fit"

​Continue:

​Once the line is drawn we must determine the "strength" of the relationship, meaning, is there an actual relationship between the sets of data and is the line we drew actually the line of best fit?

​This "strength" is given by a number known as the Correlation Coefficient. All correlations, or relationships, happen between -1 and 1. The closer to -1 or 1 the stronger the relationship

​There are three types of correlations:

1. Positive: numbers greater than zero but less than or equal to 1

2. Negative: numbers less than zero, but greater or equal to -1

3. No correlation: number equal 0​

​Types of correlation

• ​Positive correlation: Both data sets increases

• Negative correlation: One data set increases while the other decreases.

• No correlation: Changes in one data set does not affect the other data set. ​

​Types of regression that we will cover.

​Linear

​Quadratic

​Exponential

Multiple Choice

What is the correlation model of this Graph

• Linear

• Quadratic

• Exponential

• Logarithmic

Multiple Choice

What is a best-fit line used for?

• To make predictions
• To make the graph look pretty
• To connect the points
• To make it look like you know what you are doing

Multiple Choice

Which scatter plot shows no relationship?

• Graph A
• Graph B
• Graph C
• Graph D

Multiple Choice

Determine the curve of best fit.

• y = -2.7x + 7.4

• y = 0.95x² - 2.08x - 0.75

• y = -.05x - 3.26

• y = 0.95x² + 2.08x + 0.75

Multiple Choice

Which of the following quadratic equations best represents the following data?

• y = 4x² + 1

• y = 3x² + 8x - 3

• y = 4x²

• y = 3x² + 3x - 1

Multiple Choice

Is the pictured graph growth, decay, or linear or none?  

• Exponential Growth
• Exponential Decay
• Linear
• None

Multiple Choice

What is the equation of this table?

• y=512(1/4)^x
• y=32(4)^x
• y=32(1/4)^x
• y=512(4)^x

Multiple Choice

Which of the equations below represent this table?

• y=3⋅(36)^x
• y=36⋅(3)^x
• y=3⋅(⅓)^x
• y=36⋅(⅓)^x