Statistics

Assignment 3 — Hypothesis and X Variable Evaluation Due by  Wednesday Feb 15.

1. Copy and paste the data for your company revenue and quarters in a new Minitab worksheet.  The dates should be copied and pasted in column C1 and the revenue data should be copied for excel and pasted in column C2.  Find the beginning quarter for each of the X variables that you have selected and paste them beginning with the first appropriate date in column 1.  Some of the variables go back further than then revenue dates so only copy the X variable data for the relevant dates. 

2. Provide a TIme series plot for each selected X variable in your hypothesis statement and a time series plot of your company revenue.  Go to the Minitab toolbar and select Graph then select Time Series Plot from the dropdown menu.   Each of these plots can be copied and pasted into your assignment Word document submission.  
Note trend, cycle and seasonality in each plot and clearly state in the Word document if the variables show these characteristics.

3. Run a scatter plot for each X variable with your company revenue.  Go to Minitab Graph again and select “Scatterplot”.   Be sure to select the scatter plot form “With Regression” from the dropdown menu.  In the next menu select the company revenue data as the Y variable and then select the X variable to plot.  Repeat this in the menu to run all of the plots at the same time.  Copy and paste each plot (you may resize them to get several on a page) and include a statement as to whether or not the relationships are strongly, moderately or weakly linear.  (A good linear relationship is best).

4. Run correlations for each variable.  Go to the toolbar again and select “Stat” and in the pull down menu select “Basic Statistics”.  Under the next pulldown menu select “Correlation”.  Beginning with your company revenue first select it and it should appear under Variables in the menu.  Then select each of the other X variables following this.  (note that the Display p-values should be checked).  After all of your Y and X variables have been selected and appear under “Variables” select “OK”.  You will then get a correlation matrix with the correlation of each X variable appearing in the first column with its p-value underneath each correlation.  Note — p-values must be .05 or less since this is the likelihood of the correlation actually being equal to zero.  If the p-value under the variable correlation is greater than .05 then replace the variable with another variable data series.  Strong correlations are close to 1 or -1.  Weaker correlations are close to zero.  Copy the correlation matrix and place it in the Assignment Word document.  Comment on the strength of the correlations and their respective p-values.