Math 2209 Distance Minitab Assignment: Ch 25 One-Way ANOVA | Complete Solution

Math 2209 Distance         Minitab Assignment: Ch 25 One-Way ANOVA             Summer 2016
A researcher is interested to see if there is a difference in the time spent waiting in traffic for various cities in the US. Three random samples of drivers are taken from different cities (Dallas, Boston and Detroit), and the time (in minutes) that they are stuck in traffic is recorded. Is there evidence that the three cities differ in traffic wait time? This data does not require a significance level, however for the sake of practice and interpretation, we will use a significance level of α = 1%.
Dallas    Boston    Detroit
59
62
58
63
61    54
52
55
58
53
    53
56
54
49
52

Minitab Version 17 Instructions
1. Open the Minitab data file TRAFFIC.MTW from your class Moodle site.
2. Type your name and id number into the session window. 

3. Use Minitab to conduct a one-way ANOVA and residual plots, and to obtain the Tukey pairwise intervals as follows: Stat – ANOVA – One-way and specify  Response data are in a separate column for each factor level. Under Responses, add C1 Dallas, C2 Boston and C3 Detroit. Under Graphs select 3 in one then click OK. Under Comparisons click Tukey then click OK and OK.
The ANOVA output appears in the session window. Print out a copy of the Residual plots and Tukey's Simultaneous 95% CIs.
5. Print out a copy of the session window.
Once you have completed the above steps, use the output to answer the questions on the final page of this assignment. 

Make sure to submit: the page with your answers, the plots, and the session window.
There will be points for good presentation, and points taken away for poor presentation (which means write clearly and staple your pages!).

MINITAB EXPRESS INSTRUCTIONS ARE ON THE NEXT PAGE.

*Source: Texas Transportation Institute. From: Introductory Statistics, Blumenhal.
Minitab Express Instructions
1. Open the Minitab data file TRAFFIC.MTW from your class Moodle site. 
2. Use Minitab to conduct a one-way ANOVA and residual plots, and to obtain the Tukey pairwise intervals as follows: select Statistics – ANOVA – One-Way ANOVA and specify Responses are in a separate column for each factor level. Under Responses add C1 Dallas, C2 Boston and C3 Detroit. Under Comparisons click Tukey (family error rate) and under Graphs click Residual plots. Click OK.
 The ANOVA output and graph appears in the output window. Print out the output using File – Print.
3.In the Minitab spreadsheet, go to Column C4 and row 1. This means you’ll be right beside the 53 which is the first value in the Detroit column C3. Type Math2209 in this spot.

  Express on PC: Next choose Data > To Text. Enter C4 in the box Recode values in the following columns. 
   Express on Mac: Choose Data > Recode > To Text. Then enter C4 in the box values in the following columns.

  Under the box Recoded value replace Math2209 with your name and student number. Then hit OK. The output will appear in the Output window. Choose File > Print to print this output.

Once you have completed these steps, use the output to answer the questions on page 3.

Make sure to submit: the page with your answers and all your output (plots and regression output). There will be points for good presentation, and points taken away for poor presentation (which means write clearly and staple your pages!).

Math 2209        Answer Template for Minitab Assignment on Ch. 26      Name

(a)  (7 pts) Check the assumptions and state the conditions, using the residual plots where relevant. 
                
      Independence: 

               Equal Variance:

               Normality:

         (b) Is there evidence that that there is a difference in mean traffic wait time among the three cities?
         (2 pts) State the hypotheses in symbols:

(1 pt) Test Statistic:                                                                  (1 pt) P-value: 

( 3pts ) Brief conclusion: Significance:

Strength:                  
    
 
(4 pts) Conclusion (in context):  

    (c) (2 pts) Do the individual Tukey comparisons support the conclusion above? Explain in context.

d) Using the Anova table:
i) (2 pt) Calculate R2

ii) (2 pt) Calculate s