BME100 f2014:Group12 L3

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BME 100 Fall 2014 Home
Lab Write-Up 1 | Lab Write-Up 2 | Lab Write-Up 3
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Darci Botsch
Sebastian Fonseca
Jorge Espinoza
Peter Hillebrand
Devon Rusk
Krishnaa Pradhan


Descriptive Statistics


Heart Rate



Pearson R Value:-0.02885863

Heart Rate

Pearson R Value: 0.98445155


Temperature P-Value: 0.5

The T-Test for temperature shows that the data is not significant because the p-value is greater than 0.5. This means there is not a significant differnce between the two devices.

Heart Rate P-Value:0.5

The T-Test for heart rate shows that the data is not significant because the p-value is greater than 0.5. This means there is not a significant differnce between the two devices.

According to the graphs, there is a significant differnce in temperature between the spree and gold standard.


The start up company, Suntronic has asked us to test one of the latest heart rate and temperature monitors for smart phones by Spree Sports. To test the validity of the Spree Sports head band and app, temperature and heart rate readings from the device were compared to temperature and heart rate readings from oral thermometers and pulse oximeters. The readings given by the oral thermometers and the pulse oximeters are considered the gold standard.

Upon comparing the results from the Spree Sports sensor to the thermometers and pulse oximeters, several design flaws were noted.

The initial flaw noticed in the design was the bluetooth connection. The Bluetooth system of spree doesn’t work very well, so there was difficulty syncing the Spree sensor to the electronic applications on the smart phones. If the bluetooth connection cannot be improved, it is recommended that each Spree sensor come with a code that can be manually put into the application on the phone.

For the high price of the Spree headband, several factors are quite unsatisfactory. The app, for instance, has very few features. The readings for the temperature in the Spree app is based on a very ambiguous scale that doesn’t have any concrete numeric values. Instead, it gives temperature readings on a scale system from levels 1 to 4. The intervals for measuring temperature are not established and therefore an accurate reading of temperature cannot be taken from the application. It is advised that the readings detected give actual temperatures for more precise readings. Also, the Spree app is only available on iOS operating systems which puts the company at a huge disadvantage by discounting a large amount of the potential target market. This can easily be fixed by the company by making the app available to android users.

In terms of design, the Spree headband contains critical flaws. The placement of the Spree sensor only detects the external temperature, decreasing the accuracy of the temperatures given. The core temperature being maintained during exercise alters the skin temperature that is detected (on a limiting scale) by the Spree sensor. Because an internal temperature would be difficult to measure, the easiest fix for this feature is to move the location of the Spree sensor closer to the core of the body. Instead of the head band, it is recommended that the sensor be placed in a waist band or a band that can be secured around the abdomen. Also, the sensor does not fit snuggly into the headband, so it falls out very easily. An easy fix to this flaw would be to create a more secure compartment in the band for the sensor.

From the values obtained from the inferential statistics, in this case the T-test, for heart rate calculations, the spree and the gold standard groups were significant (percent error=1.6886E-5). This happened because the reading that the spree application gave for the heart rate values was fairly accurate, providing three significant figures. This fact also contributed in a Pearson correlation value closer to 1 (Pearson's R=0.984), as the measurements from the spree application and the gold standard were very similar between each other.

However, the values obtained from the T-test for the temperature calculations were not significant (percent error=7.6187E-15). The Pearson correlation was far from 1 (Pearson's R=-0.02886) because the temperature measurements given by the spree were different from the gold standard temperatures. This indicates that the Spree sensor and app have critical flaws that need to be fixed in terms of temperature readings.


Target Population and Need

The target population for the "Hydraband" will be any individual who wishes to track their hydration; in particular, the Hydraband is designed for athletes to use in order to maximize their performance. The individuals who would need the product would be anyone who wishes to be safe and efficient in their exercise. Hydration is an important part of exercise. Most athletes who do not hydrate correctly can have their performance decreased significantly if they do not consume the correct amounts of water and electrolytes that their body requires. Additionally, sometimes excess dehydration can lead to severe life threatening conditions, and this why it is important to constantly monitor how much water the athlete's body is loosing over a period of time. At the present time, there are no other devices that give an accurate reading of the dehydration levels the body when in exercise. Although other companies have created other prototypes that measure dehydration levels, their design features are not adequate for use by an athlete. On the contrary, the Hydraband is light and has several practical attributes that make it perfect for any sport at any time.

Device Design

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Inferential Statistics

In the table below, the readings given by the Hydraband are given in terms of the color that was shown in the device when the test subject was perfroming the physical activity. It is important to highlight that the ranges for each color are as follows:

Green: 0%-0.5% water loss. Yellow: 0.5%-2% water loss. Red: 2%-3% water loss.

The gold standard test that was carried out to test the validity of the hydraband was a urine test to examine the percent of water lost by the test subjects' bodies and the concentration of several ions in the urine samples.

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The following table illustrates the mean, the median and the standard deviation for the gold standard values that were obtained in the experiment. Since the hydraband does not provide a specific set of values for each measurement, there is no exact way to calculate these descriptive statistics for the device.

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The following table shows the inferential statistics that were calculated for the two sets of data in the experiment (gold standard and hydraband). It is important to highlight that the values that were used as the averages for the hydraband are the median values of the range for each given color.

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Graph of the averages of the Hydraband readings and the gold standard values during low, medium and high intensity excercise intervals.

Since the T-Test value is close to 0.99 (p>0.05), it can be stated that there is no relative significance between the two sets of data. This means that the values that were yielded both by the gold standard and the hydraband were very similar among each other, proving the validity of the new biomedical device.