Seal team 6 Flashcards
You have multiple independent variable X
relationship between x and y is described as a linear function
Do you have a simple linear regression?
NO
You have only ONE independent variable x
The relationship between x and y is explained by a linear function
Do you have a simple linear regression?
Yes
If there is a wide distribution of the variables from the line do you have a strong or weak relationship?
Weak
Can you make assumptions outside the range of data in a linear regression?
No - it did not work out well for NASA
Correlation tells us -
how strong the relationship is
Regression helps us predict one factor from the other
True or False
True
In regression analysis, what is the null hypothisis
Ho - there is no relationship
H1 - there is a relationship
Is there a causal effect implied with correlation?
No - Correlation analysis is used to measure the strength of the association (linear relatioship) between 2 variables
Correlation is only concerned with strength of the relationship
there is no causal effect with correlation
Regression analysis is used to:
Predict the value of a dependent variable based on the value of at least one independent variable
Explain the impact of changes in an independent variable on the dependent variable.
Ie.e change in sq feet of the store ompact on sales
What are the 2 types of relationships
Linear and curvilinear
How do you draw a relationship along a curvilinear relationship
you must break it in to parts on analyze the linear portions independently.
What is the Simple Linear Regression Equation
Yi = bo +b1Xi Y = Estimated value for for observation i bo = Estimate of the regression intercept Bo b1 = Estimate of the slope of B1 X= value of X for observation i
The Least Squares Method
Used to find bo and bi terms in the regression
what is bo
The estimated mean value of Y when X is zero
what is bi
estimated change in the mean value of Y as a result in a 1 unit change in x
What do you choose in PH Stat to run a simple linear regression?
Simple Linear Regression
In the house price example where square feet is used to predict price:
IF the coefficients in PH stat are
intercept = 98.24833
Sq ft = .10977
What is the regression equation
House price = 98.24833 + .10977(times square feet)
The coefficient of determination is also known as
r2
R squared
What is the measure of total variation
SST - Total Sum of Squares
measures the variation in Y1
values around their mean Y
