Temperature:
Oral (Gold Standard) In Lab
Mean: 96.87 degrees Fahrenheit
Standard Deviation: +/-1.78 degrees Fahrenheit
Standard Error: +/-0.15 degrees Fahrenheit
Sensor In Lab
Mean: 97.48 degrees Fahrenheit
Standard Deviation: +/-1.12 degrees Fahrenheit
Standard Error: +/-0.09 degrees Fahrenheit
Oral (Gold Standard) Outside
Mean: 96.42 degrees Fahrenheit
Standard Deviation: +/-1.70 degrees Fahrenheit
Standard Error: +/-0.13 degrees Fahrenheit
Sensor Outside
Mean: 97.51 degrees Fahrenheit
Standard Deviation: +/-1.36 degrees Fahrenheit
Standard Error: +/-0.10 degrees Fahrenheit
Blood Pressure:
Blood Pressure Cuff (Gold Standard) Pre-Walk
Mean: 119.38 mmHg
Standard Deviation:+/-14.81 mmHg
Standard Error: +/-1.67 mmHg
Watch Sensor Pre-Walk
Mean: 113.99 mmHg
Standard Deviation:+/-14.63 mmHg
Standard Error:+/- 1.65 mmHg
Blood Pressure Cuff (Gold Standard) Post-Walk
Mean: 120.49 mmHg
Standard Deviation:+/-18.87 mmHg
Standard Error: +/-1.36 mmHg
Watch Sensor Post-Walk
Mean: 113.40 mmHg
Standard Deviation:+/-13.20 mmHg
Standard Error:+/- 0.95 mmHg
Pulse:
Pulse Ox (Gold Standard) Pre-Walk
Mean: 83.03 beats per minute
Standard Deviation: +/-13.76 beats per minute
Standard Error: +/-1.54 beats per minute
Watch Sensor Pre-Walk
Mean: 81.21 beats per minute
Standard Deviation: +/-10.76 beats per minute
Standard Error: +/-1.20 beats per minute
Pulse Ox (Gold Standard) Post-Walk
Mean: 86.70 beats per minute
Standard Deviation: +/-19.21 beats per minute
Standard Error: +/-1.39 beats per minute
Watch Sensor Post-Walk
Mean: 84.19 beats per minute
Standard Deviation: +/-18.33 beats per minute
Standard Error: +/-1.32 beats per minute
Results
Analysis
We completed a T-Test for all three comparisons because there were two groups for each experiment. The T-Tests are paired because both tests were completed on the same person.
T-Test Results:
Temperature:
In Lab: p value= 0.0001
Outside: p value= 0.0000
Blood Pressure:
Pre-Walk: p value= 0.0123
Post-Walk: p value= 0.0000
Pulse:
Pre-Walk: p value= 0.0677
Post-Walk: p value= 0.0023
This means that there was a significant difference between the temperature and blood pressure reading because the p values were below 0.05. However, for the pre-walk pulse readings the p value was above 0.05 and this means that there was not a significant difference. The fact that there was not a significant difference between the pulse during the pre-walk means that the tested device was working accurately.
We also completed Pearson tests to see the correlation between the two readings. A Pearson r value close to 1 would mean that there was a positive correlation, a value of -1 would mean a negative correlation and a value of 0 would mean no correlation.
Temperature:
In Lab: r value= 0.1740
Outside: r value= -0.0410
Blood Pressure:
Pre-Walk: r value= 0.1923
Post-Walk: r value= 0.3110
Pulse:
Pre-Walk: r value= 0.7718
Post-Walk: r value= 0.8224
Since all of the r values for temperature and blood pressure are very close to zero, it shows that there is no correlation between the device readings for all these comparisons. This infers that the tested devices were not accurate or correlated with the gold standards. This concludes that the devices were giving off faulty readings. The pulse r values were close to 1 which means that the readings were correlated. This again confirms that the pulse readings were similar and the device was more accurate than the others tested.
Summary/Discussion
Temperature:
When we were recording the results we noticed many flaws with the sensor temperature readings. Twice the temperature readings from the sensor jumped from 102 to 94 within the 5 minute interval of walking around. This was not consistent with her reading on the oral temperature and it does not make any logical or natural sense. It seemed like these happened when we went from being outdoors to entering a building. It seems like the flaw is that it is reading skin temperature when can vary by changing locations whereas the oral thermometer was reading internal temperature. Another flaw was the inconvenience and it being uncomfortable to have the sensor under the armpit at all times. We also had issues with the sensor losing connection with the iPhone.
The biggest recommendation is to find a way to calculate the temperature based on a more accurate reading than skin temperature. To make it more convenient and also be connected to technology, it should be considered making a temperature sensor that can go in a person's ear since that is a good place to read internal temperature. A possibility is looking into adding a temperature sensor into headphones that go into the ear.
Blood Pressure:
The flaws in the blood pressure watch sensor were that you had to raise your arm to chest level to get an accurate reading. Also, often times it had an error on the screen so it wasn't as reliable as the gold standard blood pressure cuff. Another major flaw is that it is reading your blood pressure off on secondary arteries in your wrist and not the main brachial artery in the arm. Blood pressure varies depending on what location you take it on your body. A recommendation is to make a blood pressure cuff that can go around the bicep that is similar to the one that goes on the wrist. If it could be smaller in width and yet still get the accurate blood pressure reading electronically, I think more people would be interested in that. It would be even better if they could integrate that technology into the current Fit Bit and other fitness trackers that go on the bicep.
Pulse:
The watch sensor had some flaws on reading the accurate pulse. During our experiment, the watch sensor showed that the pulse went from 78 to 131 back to 74 during a 15 minute interval. During this 15 minutes, the group member that was being tested was sitting the entire time with no activity. So again, there was no logical or natural explanation as to why the pulse would almost double then normalize over that time interval. Recommendations for the watch sensor in regards to reading the pulse is calculating the pulse at different times than the blood pressure because the blood pressure and restricting of the arteries will not give accurate reading. Also, the watch sensor was large and cumbersome compared to the pulse ox so it would be good to find a smaller, more effective way to measure pulse.
LAB 3B WRITE-UP
Target Population and Need
We have created Body Beatz, ear phones that measure heart rate. The target population is athletes, people who work out and/or want to lose weight. This is our primary target population because they work out on a regular basis and are concerned about their heart rate. This device easily attaches to any smart phone and monitors heart rate with a sensor in the ear phones that then communicates with a free app. The target population needs this product because the current heart rate monitors on the market require a monitor that is strapped around the body at the heart level and a wearable monitor it communicates with. By putting the heart rate monitor into the ear phones with Body Beatz, consumers will not have to wear additional monitors. Another perk of the device is that it will notify the consumer if their heart rate is above or below the targeted heart rate. This is valuable to the consumer because it allows them to maximize their workout by staying in the targeted heart rate.
Device Design
Body Beatz ear phones
Inferential Statistics
Data Set:
Gold Standard
Heart Rate Monitor
Body Beatz
(beats per minute)
(beats per minute)
76
76
81
82
70
73
72
74
96
97
98
101
88
91
68
71
80
80
98
101
94
94
64
65
95
98
69
69
64
67
68
68
88
91
84
86
91
93
76
76
78
81
61
61
69
72
85
87
84
85
92
94
90
90
60
59
100
97
65
62
100
99
84
83
66
64
67
64
92
90
79
77
67
64
66
63
98
96
65
63
68
65
78
77
67
65
82
82
84
83
84
82
98
97
92
92
61
61
82
80
69
69
Descriptive Statistics:
Heart Rate:
Heart Rate Monitor (Gold Standard)
Mean: 79.47 beats per minute
Standard Deviation: +/-12.36 beats per minute
Standard Error: +/-1.73 beats per minute
Body Beatz
Mean: 79.55 beats per minute
Standard Deviation: +/-12.89 beats per minute
Standard Error: +/-1.81 beats per minute
The t-test shows that there is no significant difference between the gold standard heart rate monitor and the Body Beatz ear phones. This is true because the t-test value is larger than 0.5. By not showing a significant difference, the Body Beatz device can be considered accurate for measuring heart rate. The pearson r value is close to positive one which means that there is a positive correlation between the gold standard heart rate monitor and the Body Beatz device. This again confirms that the Body Beatz device is accurate and an effective way to measure heart rate.
BME 100 Fall 2013
