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Keeping it Hot. A Project for STATS 542 With Dr. Heather Smith By Eliot Aretskin-Hariton Full presentation available at: http:// ehariton.weebly.com/stat542.html. Research Question. Which cup is best for keeping my tea as hot as possible over different periods of time? . Hypothesis.
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Keeping it Hot A Project for STATS 542 With Dr. Heather Smith By Eliot Aretskin-Hariton Full presentation available at: http://ehariton.weebly.com/stat542.html
Research Question • Which cup is best for keeping my tea as hot as possible over different periods of time?
Hypothesis • Ho: The effect that time has on water temperature DOES NOT depend on the type of cup. • Ha: The effect that time has on water temperature DOES depend on the type of cup
Pilot Study #1: Fail • Factors: • Cup Type: Contigo, Ceramic, Starbucks • Wait Time: 30 min, 60min, 120 min • Replicates 5 • Experimental Unit: A Pour • Randomized testing procedure • Failed due to inability to take accurate readings using temperature measurement equipment
Revised Data Capture Methods • Set standoff distance from fluid of 6” • Attach stirring rod to IR thermometer to mix fluid • Use fan to gently blow away excess steam rising from surface of liquid
Experimental Procedure • Boil water and pour into fill line of cup and seal with lid • Wait specified amount of time • Unseal cup, stir cup for 2 seconds with spoon attached to IR thermometer. • Rest IR thermometer on edge of cup and sample for 10 seconds, fanning gently to prevent steam from reaching the device • Repeat for all treatment levels
Pilot Study #2: SuccessExperimental Design • Reduced cup types and wait times to those with expected maximum difference • Factors: • Cup Type: Contigo, Ceramic • Wait Time: 30 min, 120 min • Replicates 5 • Experimental Unit: A Pour • Randomized testing procedure
Pilot Study #2: Dot Plot • Between Variation is LARGE • Within Variation is SMALL • Ended pilot study data collection at 3-4 replicates for each treatment
Main Study: Experimental Design • Factors: • Cup Type: Contigo, Ceramic, Starbucks • Wait Time: 30 min, 60 min, 90min, 120 min • Replicates 2 • Experimental Unit: A Pour • Blocking Factors: None • Randomized testing procedure
Main Study: F-Test • P-Value for Interaction Term is much less than 0.05 • Reject Ho and accept Ha: The effect that time has on water temperature DOES depend on the type of cup
Conclusions • The longer you wait, the worse the Ceramic cup performs. • At 30 minutes, the Contigo and Starbucks cups have statistically similar performance. • At 60 minutes and beyond, there is a statistically detectable difference between Contigo and Starbucks which widens as wait time increases. • The Contigo cup performed the best overall in keeping the water HOT!
Recommendations • Use a Cup as the experimental unit rather than a pour. • Test a wider variety of standard cups. • Increase replicates a bit for more power at 30 minutes so that well can tell if Starbucks or Contigo is better for this time period.