Below you are given the examination scores of 20 students (data set also provided in accompanying MS Excel file).
Shown below is a portion of a computer output for a regression analysis relating supply (Y in thousands of units) and unit price (X in thousands of dollars).
- What has been the sample size for this problem?
- Determine whether or not supply and unit price are related. Use α = 0.05.Determine whether or not demand and unit price are related. Use α = 0.05.
Compute the coefficient of determination and fully interpret its meaning. Be very specific.
- Compute the coefficient of correlation and explain the relationship between supply and unit price.
- Predict the supply (in units) when the unit price is $50,000.
Allied Corporation wants to increase the productivity of its line workers. Four different programs have been suggested to help increase productivity. Twenty employees, making up a sample, have been randomly assigned to one of the four programs and their output for a day's work has been recorded. You are given the results below (data set also provided in accompanying MS Excel file).
- Construct an ANOVA table.
- As the statistical consultant to Allied, what would you advise them? Use a .05 level of significance.
A company has recorded data on the weekly sales for its product (y), the unit price of the competitor's product (x1), and advertising expenditures (x2). The data resulting from a random sample of 7 weeks follows. Use Excel's Regression Tool to answer the following questions (data set also provided in accompanying MS Excel file).
- What is the estimated regression equation? Show the regression output.
- Determine whether the model is significant overall. Use α = 0.10.
- Determine if competitor’s price and advertising is individually significantly related to sales. Use α = 0.10.
Based on your answer to part (c), drop any insignificant independent variable(s) and re-estimate the model. What is the new estimated regression equation? Interpret the slope coefficient(s) of the model from part (d).