project worksmart

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Instructions:  To complete this project, you will need the following materials:

  • Statdisk User Manual (link found on Project resources page)
  • Access to the Internet to download the Statdisk program.
  • You don’t have to explain your steps unless the problem specifically says to.

Part I.  Analyze Data

InstructionsAnswers
Open the file Old Faithful using menu option Datasets and then Elementary Stats, 13th Edition.  This file contains information on the characteristics of Old Faithful eruptions.  Details of the data is given at the end of this file.  How many observations are there in this file?   
What results do you expect to find in this data relating the duration and height? 

Part II. Descriptive Statistics

3-6 Generate descriptive statistics for all three groups of people and complete the following table.  Round all results to 2 decimal places.VariableSample MeanSample Standard DeviationSample Size
Interval Before   
Duration   
Height   
7. Did you get the results you expected here?  Explain why. 
8. In which of the three groups did we experience the MOST variation?  What measurement would you use to determine this? 

Part III. Confidence Intervals

  9. Generate a 95% interval for the hanging mean Interval Before. Paste your results here. 
10. Generate a 95% interval for the mean of Duration. Paste your results here. 
11.Generate a 95% interval for the mean of Height. Paste your results here 

12. Create a graph below by illustrating all three confidence intervals on one graph using the tools in your word processor (example below).  Stat isk cannot do this for you. Create your graph and turn the font red.  For this process, I just used dashes and wrote a scale below the axes.  Be sure to choose a scale that show the relationship between these variables.

    Here is an example, but it is not based on the data you are analyzing:              Case 1                         14———————42            Case 2                                               35————————-70                                    ________________________________________                        0                20                 40                 60
 Your Solution:    
13. Based on the confidence intervals shown above, does there appear to be some evidence to indicate duration is related to height?    

Part IV. Hypothesis Testing

    14.  You and your family are on a vacation to Yellowstone and want to see the eruption of Old Faithful.  However, as you approach the geyser it is completing an eruption.  The park ranger says that the average time to wait for the next eruption is 88 minutes (interval after). Use the data for interval after in the Old Faithful data set to test the claim, that the time is more than 88 minutes.    Use an alpha of 0.05.

Step 1.  Determine parameter of interest and state the null and alternative hypotheses. 
Step 2.  Determine the sample mean, sample standard deviation, and sample size.  [Hint:  You did this in an above step in this assignment.]  You can also select Use Data from the Statdisk menu instead. 
Step 3.  Determine the likelihood that the population mean is greater than 88 minutes by completing a Hypothesis Test: One Mean in STATDISK.   Use significance of 0.05.  Paste results here. 
Step 4.  State your conclusion. The conclusion statement has a prescribed format: it should include a comparison of the p-value and alpha, whether you reject or support the null hypothesis, and a verbal statement of which hypothesis is supported. 

15. Now, test the claim that the duration of the eruption is less than 235 seconds   Use a significance level of 0.01. 

Step 1.  Determine parameter of interest and compose null and alternative hypotheses. 
Step 2.  Determine the sample mean, sample standard deviation, and sample size.  [Hint:  You did this in an above step in this assignment.] You can also select Use Data from the Statdisk menu instead. 
Step 3.  Determine the validity of the claim that the mean duration of eruption is less than 235 seconds by completing a Hypothesis Test: One Mean in STATDISK.   Use significance of 0.01.  Paste results here. 
Step 4.  State your conclusion.  The conclusion statement has a prescribed format: it should include a comparison of the p-value and alpha, whether you reject or support the null hypothesis, and a verbal statement of which hypothesis is supported. 

16. Answer the following questions based on the above hypothesis test.

What is the p-value in this example and what does it represent? 
Given that your data, hypotheses, and p-value do not change, what would need to be changed in order for us to FAIL TO REJECT the null hypothesis?   

Int Before is the interval before the next eruption in minutes

Duration is the length of the eruption in seconds

Interval After is the interval after the eruption in minute

Height in the height of the eruption in feet

Pred Error is the prediction error in minutes

Submit your final draft of your Word file by going to Week 4, Project, and follow the directions under Week 4 Project.  Please use the naming convention “WK4Proj+last name+first initial.” as the Submission Title.