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I am using x to predict y. When I know the value of x, the mean-squared-error of my
estimate of y is less than when I don't know x. - answer-x explains some of the
variance in y
If the SSmodel is greater than the SSresidual... - answer-the model accounts for
more than 50% of the total variance
What is the coefficient of determination? - answer-The proportion of variance
accounted for in the dependent variable by the predictor variables.
What is the relationship between r and beta in a simple regression? - answer-beta is
an unstandardised measure of r
What is the critical value for t with 5 degrees of freedom and an alpha of 0.05 two-
tailed? Give your answer to 2 decimal places. - answer-2.57
You have the following data:
x = c(10,3,2,1,3,4,5,6)
y = c(2,14,18,12,10,11,8,9)
You run a linear model and get the following estimate of the slope:
^B1 = -1.423
What is the standardised beta? Report to 2 decimal place - answer--0.86
If I have a lot of error in my regression model, it means that: - answer-There are big
differences between the line specified by my model and the corresponding points on
the scatterplot.
If the beta for your x term in a regression model is negative, it means: - answer-That
there as x increases, y decreases.
I conduct a study to investigate whether average hours of sleep per nigh (x) predicts
sick days per year (y). I find the follow values for the intercept and slope:
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,CWP test with 100% correct answers
2024
B0 = 25
B1 = -1.6
True or false, the following is the correct interpretation of the intercept:
A person who sleeps 0 hours on average per night is expected to have 24 sick days
per year. - answer-False
I conduct a study to investigate whether average hours of sleep per nigh (x) predicts
sick days per year (y). I find the follow values for the intercept and slope:
B0 = 25
B1 = -1.6
True or false, the following is the correct interpretation of the slope:
For every hour of sleep a person has on average per night, the number of sick days
per year decreases by 1.6 days. - answer-True
What is the critical value for t with 5 degrees of freedom and an alpha of 0.01 two-
tailed? Give your answer to 2 decimal places in the form X.XX - answer-4.03
You run a linear model with a single binary predictor. The intercept for the model is
110, and the unstandardized beta is 17.1. What is the mean of the group coded 1? -
answer-127.1
You run a linear model with a single binary predictor (0 = Group0; 1 = Group1). The
mean of Group1 is 75 and the beta coefficient is 7. What is the value of the
intercept? - answer-68
If regression model errors (residuals), show different amounts of variation across the
range of measurement, they are referred to as ... - answer-Heteroscedastic
Match the assumption/diagnostic to the most appropriate test.
Shapiro-Wilk Test - answer-Normality of residuals
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, CWP test with 100% correct answers
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Match the assumption/diagnostic to the most appropriate test.
Durbin-Watson Test - answer-Autocorrelation of residuals
Match the assumption/diagnostic to the most appropriate test.
Non-constant variance test - answer-Heteroscedasticity
Match the assumption/diagnostic to the most appropriate visualization.
Histogram - answer-Normality of residuals
Match the assumption/diagnostic to the most appropriate visualization.
Scatterplot - answer-Linearity
Match the assumption/diagnostic to the most appropriate visualization.
Residual-vs-predicted plot - answer-Heteroscedasticity
The null hypothesis for the non-constant variance test (Breusch-Pagan test) is that
the data are heteroscedastic.
True or False? - answer-False
What are the degrees of freedom for the sums of squares total in a linear model? -
answer-n-1
Which R function can be used to calculate from a model object? - answer-predict()
In a simple linear model where both variables are continuous and z-scored, what is
the value of the intercept? - answer-0
The null hypothesis for the non-constant variance test (Breusch-Pagan test) is that
the data are heteroscedastic. True or false? - answer-False
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