BME100 s2015:Group2 12pmL3

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BME 100 Spring 2015 Home
Lab Write-Up 1 | Lab Write-Up 2 | Lab Write-Up 3
Lab Write-Up 4 | Lab Write-Up 5 | Lab Write-Up 6
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Name: Levi Riley
Name: Alexandria Clark
Name: Blossom Mendonca
Name: Alina Kilic
Name: Trevor Douglass
Name: Andre Dang


Descriptive Statistics

Descriptive Stats of Data


Graph of Heart Rates

Graph of Temperature


T-Test of Heart Rate

Pearson's R HR

T-Test of Temperature

Pearson's R Temp


The t-test was used to determine significance because the comparison was between two groups, Gold Standard and Spree. The t-test values of 7.36E-19 and the alpha value of 0.05 for temperature yielded that the data was statistically significant from one another. This means that the alternative hypothesis - that there is a difference between these two devices - was accepted. As a consequence, the null hypothesis stating that there is no difference between the devices was rejected. This T-Test value shows that there is a very significant difference between the two data meaning that Spree and Gold standard do not correlate with one another as proved by the Pearson's R-Correlation test which yielded a value of -0.0517. The t-test results for heart rate showed no significance as the value was 0.321 compared to 0.05. This means that the alternative hypothesis - that there is a difference between these two devices - was rejected. As a consequence, the null hypothesis stating that there is no difference between the devices was accepted. This is due to the fact that since the data collected showed so significant difference between the groups, they must correlate in some reasonable amount as proved by the Pearson's R Correlation result of 0.57612.


From the experience of using the Spree device, the group came across several design flaws in the device. The first major flaw that we discovered, was that the temperature gauge was on a scale from 1-4, rather that giving an exact value. The Spree headband advertises that the headband can read the users' temperature; however, that is not the case. To fix this flaw, our group recommends that the Spree device simply uses a temperature value rather than an ambiguous scale.

Another flaw the group came across was that the Spree headband shut off each time the user stopped moving. This may be a problem for the user because they may not want to restart their headband every time they stop moving. Many users would take breaks during their workouts so a device which stops working would cause the workout information to be lost to the user. To fix this flaw, our group recommends that the headband has a time limit of two minutes without sensing motion before it shuts off because users may want to take a short break in between their workouts.

When programming the device and trying to get the device synced to the phone via Bluetooth, the group found that it was difficult to do so when other Spree devices were present. The device shows up as a mixture of letters and numbers. This could be very aggravating to the user because if someone else in the vicinity is using a Spree - the user may not know which device they are supposed to sync to. The group recommends that the Spree device be made programmable in such a way that the user can enter whatever name they want for their device so that anytime they sync their Spree headband to their phone, it is obvious which Spree they are connecting too.

Besides the technical flaws, there are many flaws regarding the aesthetics of the device. he headband was very uncomfortable due to the fact that it created a tremendous amount of heat on the forehead, and also it was also very tight. It could also be distracting during the workout due to the fact that it is on your forehead and the buildup of heat causes drops of sweat to go directly downward into the eyes. The headband is also very unattractive which may prevent some users from wearing them in public. Our group recommends that they design the object to be used on a different part of the body besides the head or design it in such a way that it has a lightweight, breathable material which does not cause a buildup of heat on the forehead. Also, the device should be more fashionable such as different colors or styles which make it look more like an athletic headband and less like a measurement device.

Overall, this device is unappealing and contains many design flaws that make it not beneficial for the user. It is also very expensive making it questionable in terms of getting ones' money worth from buying the device.


Target Population and Need

Target Population:

The Hydro-Ring targets any person who is able to wear a ring or necklace and clasp. The clasp and ring allow for a gender neutral target. Any person who wants to stay healthy, hydrated, and have optimal performance (sports, weight-loss, etc) can wear and use this device. Dehydration is a big problem in many states which experience warmer climates. In the United States alone, approximately 500,000 people annually receive some form of medical attention due to dehydration. Dehydration serves as a big problem because a loss of as little as 3% of body mass water percentage increases one risk of heart illness and organ failure. In the United State, the southern states - typically from South Carolina stretching South and West all the way to California - experience the highest prevalence of medical care needed due to dehydration. These people face warmer and more humid climates than many places in the United States, and as a result, sweat more frequently leading to a loss of water and an increased prevalence of dehydration. The 500,000 people and others like them who experience this harsh climate annually, could make use of the Hydro-Ring which integrates hydration analysis into a fashionable and convenient device designed to help those in this climate stay healthy and hydrated.

Needs: Performance begins to decrease at 1-2% dehydration, at 3% dehydration the risk of heart illness significantly increases. The average person, without exercise, looses 90 ounces of water per day. This means even non-athletes loose a significant amount of water each day, and are at risk of dehydration. If dehydration reaches levels of 7%, those people can collapse. Not only is staying hydrated optimal for one's health, staying hydrated can also increase weight loss, decrease hunger, and balance the metabolism. This leads to an overall increase in health. These health needs are found in all people and the Hydro-Ring reaches all these needs by alerting people when they come out of the optimal hydration range. The device alerts them when they need fluids and how much they need to consume in order to reestablish hydration. Many people use thirst as a guide of when they should drink; however, once a person is thirsty they are already dehydrated. This device alerts the user before they feel thirsty and before they are already dehydrated. This is accomplished by linking the microsensor in the device to a phone app via Bluetooth. The ring is always on and the contents of the person's sweat and is constantly being analyzed by the processing chip under the microsensor. When a person begins to become dehydrated or their hydration levels begin to fall - the app sends a notification to the user and tells them how much to drink. This meets the needs of a society where dehydration is an issue due to a warm climate. Instead of having to worry to remember to drink water even when they're not thirsty, the ring and app does this for them. This is important as a means to help those in warm climates stay hydrated as a means to preserve their health.

Device Design



Product Variety, Affordability, Appearance Customer Needs

Durability,Material Selection, Focus Test Groups Engerineering Requirements

Weakest: Accuracy, Energy Consumption, Manufacting Process Engerineering Requirements

Efficiency Customer Needs


Product Variety vs. Material Selection: The hydroring offers a variety of product lines including different types of material selection per product.

Product Variety vs. Focus Group Testing: Three different age groups (young teens, young adults, seniors) agree that the product variety was appealing.

Affordability vs. Material Selection: The materials are outsourced through third party manufacturers making our product lines affordable.

Appearance vs. Material Selection: Stylish sleek appearance while using affordable materials.


Energy Consumption vs. Product Variability: Only offers one type of battery and uses a lot of energy when measuring.

Reliability vs. Manufacturing Process: Quality control is not the best because of third party manufacturers.



Inferential Statistics


IN order to obtain these statistics results, the following was done. Fifty test subjects of various age, ethnicity, and body composition were gathered and asked to take part in this experiment. In the first part of testing, the subjects were adequately hydrated by consuming one gallon of water per person. Each person was asked to consume this water within an eight hour time period. During this eight hour period, the subjects were kept inside the lab in order to ensure that environmental conditions were as close as possible to minimize error in the measurements. After this span of eight hours, the subjects rested in the lab for an additional two hours to let the water process through their bodies. After this, the gold standard and Hydro-Ring measurements were taken.

Because the Hydro-Ring analyzes the electrolyte concentration of sweat in order to test hydration levels, the Gold Standard comparison used was an urinalysis of the kidneys. This analysis checked the electrolyte concentration of the kidneys in order to get a direct measurement for how dehydrated a person may be. The more dehydrated, the higher the concentration of electrolytes. The more hydrated, the lower the concentration of electrolytes due to the dilution of the electrolytes.

Each patient's electrolyte concentration in grams per milliliter was taken via Gold Standard and via the Hydro-Ring. After measuring each person, the second phase began. The test subjects were denied water for an eight hour period and kept in the lab. This functioned to adequately dehydrate the test subjects and therefore change the concentration of electrolytes in their bodies. After these eight hours, their electrolyte concentrations were once again taken using Gold Standard and the Hydro-Ring.

After these measurements were taken, a T-Test was used in order to compare the difference in the measurements of Gold Standard and Hydro-Ring. A T-Test was ran for each part of the experiment - hydration and dehydration phase. Because there were only two groups of comparison - Gold Standard and Hydro-Ring - only a T-Test needed to be ran.

When subjects were adequately hydrated, the T-Test yielded that there is no statistical significance between Hydro-Ring and Gold Standard. This means that the two yield measurements very close to one another. When subjects were dehydrated, the T-Test revealed that there is no statistical significance between Hydro-Ring and Gold Standard.

The results of these statistics reveals that the Hydro-Ring is accurate and comparable to Gold Standard measurements.




These graphs summarize the data gathered throughout the product testing. In both graphs, the yellow bar represents Gold Standard where the blue bar represents Hydro-Ring. Each graph is the mean electrolyte concentration of its respective test group. The error bars are also included in each graph to show standard deviation of each group. As a quick disclaimer, while the two groups may seem very far apart it is necessary to notice the scale on the y-axis for each graph. In the graph of average electrolyte concentration in dehydrated test subjects, the scale is to 0.00001 g/mL while the graph of average electrolyte concentration in hydrated test subjects is set to a scale of 0.00002 g/mL. Because the y-scale is so small, any slight difference in data makes the graphs appear to be very different from one another; however, based upon the actual numerical means, standard deviations, and T-Test values, this is not the case.