ITEC 601 Exam 5

ITEC 601 Exam 5 | Assignment Help | Kogod School Of Business Of American University 

1.      Simple Linear Regression. Reed Auto periodically has a special week-long sale. As part of the advertising campaign Reed runs one or more television commercials during the weekend preceding the sale. Data from a sample of 10 previous sales are shown in the table.

a)      (1 point) Draw a scatter diagram of the data. Comment on whether it appears that a linear model might be appropriate.

b)      (1 point) Determine the least squares regression line. Interpret.

c)      (1 point) Estimate the number of cars sold when the number of ads is 4.

d)       (1 point) Interpret the coefficient of determination.

e)      (2 points) Test at 0.05 significance level to see if there is an evidence of a linear relationship between TV ads and cars sold in your sample?

2.      Multiple Regression Using simple linear regression, we want to find out how the weight of the children varies with their height and age, and to verify if a linear model makes sense. The data have been obtained in Lewis T. and Taylor L.R. (1967). Introduction to Experimental Ecology, New York: Academic Press, Inc. They concern 237 children, described by their gender, age in months, height in inches (1 inch = 2.54 cm), and weight in pounds (1 pound = 0.45 kg). Please download “Data_assignment2.xlsx” from file section of 2KSB for solving this question.

a)      (2 point) Develop a multiple regression model to find how the variability of the Weight is explained by the Height and the Age

b)      Provide the output of the multiple regression model, including the numerical values for the parameter estimates (use four significant digits), the R-squared and adjusted R-squared values. Copy and paste all related tables of your model from the statistical package that you use to build the model into your report as an image.

c)      c) (1.5 point) Test the global usefulness of the multiple regression model in part a using Ftest at 0.01 significance level.

d)      (1.5 point) Test at significance level 0.01 if the coefficient of variable Age is statistically different from 0.

e)      (2 point) For each independent variable (Age and Height) explain in a sentence what the coefficient of an independent variable means. Hint: e.g., an increase of 1 year in age increases (or decreases) the weight.