BME100 s2015:Group4 9amL3

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Owwnotebook icon.png 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: Aaron Frisby
Name: Alexandra Torres
Name: Measho Habtemichael
Name: Cody Manning
Name: Your name
Name: Amanda Nguyen


Descriptive Statistics

Spree Mean: 94.9886264 degrees
Spree Standard Deviation: 2.85469695 degrees
Golden Standard Mean: 97.2556818 degrees
Golden Standard Standard Deviation: 1.19566823 degrees

Heart Rate
Spree Mean: 101.9515 beats/min
Spree Standard Deviation: 34.33868 beats/min
Golden Standard Mean: 94.88349515 beats/min
Golden Standard Standard Deviation:30.84092677 beats/min



Here is the graph illustrating the mean temperatures recorded by the Spree and the gold standard. Meantemperature.jpg

Here is a scatter plot with a trendline, representing the correlation between the points. Temperaturepearson.jpg

Heart Rate

Bar graph that represents the average mean heart rate of the Spree and the Gold Standard

Bar graph.png

Scatter Plot of the Heart rate correlation between the Spree and Gold Standard

Spreegold scatter plot.png



In analyzing the data, a t-test will be used because only two groups are being compared. After the test, the value found was 1.08*10^-10. Because this value is less than the alpha value of 0.05, there is a statistically significant difference between temperatures taken using the Spree and the temperatures from the gold standard.
After using the Pearson correlation test, the r-value was found to be 0.00667. This value is closer to 0, showing that there is no correlation between the values found between the Spree and the values from the gold standard.

Heart Rate

After retrieving all of the heart rate data the t-test was used on the Spree group and the Gold Standard group. This particular test was chosen because we are only comparing two groups as state before. The t-test value was 0.000345. This is very small and falls far below the alpha value of 0.05. With that said, this means that there is a significant difference between the heart rate values in both of the groups. However, when looking at the Pearson's R value it says otherwise. The R value was recorded to be 0.6867 which is close to 1. This suggests that there is a positive trend when comparing the groups and that they correlate to each other.


In conclusion, it can be determined that the Spree is not a useful device to measure temperature. According to the t-test, the value was lower than the alpha of 0.05, meaning that there is a statistically significant difference between the temperatures found using the Spree and the temperatures from the gold standard. When testing the Spree, the t-value determined should have been greater than 0.05 to imply that there is no difference between the devices. The t-value less than the alpha means that the Spree is not an accurate measure of heart rate. The Pearson r correlation value was found to be 0.00667. The expected r-value should have been around 1, in order to imply that the Spree is an accurate measure of heart rate. The actual value is close to zero, meaning that there is no correlation between the temperature values using the Spree and the gold standard. There may also be errors with this data, because the device is not an accurate measure of temperature. Instead of giving an actual value for temperature, different temperature levels are given by color.

When using the data in the heart rate, some data points needed to be removed, because of inaccuracies. Some values were recorded as zero while other points had two data points recorded. The t-test value recorded was 0.000345 which is far lower than the alpha value of 0.05. This represents the statistical difference between the groups and it illustrates that they cannot be compared. Although, when observing the Pearson's R value, it shows that there may be a positive trend between the groups. The R value came out to be 0.6867 which is relatively close to one and represents a possible positive correlation for the groups. Possible errors to this data could be the fact the Spree information is transferred via Bluetooth which can have interference. Also, the timing of taking the measurements is critical and if both values are not taken simultaneously then there can be inaccuracies between both the Spree and the Gold Standard.

There are many changes that can be done to the Spree. The device itself needs to be altered in order to provide a more accurate means of measuring temperature. Aesthetically, the device is unattractive and uncomfortable to the user. The Bluetooth connection between the device and phone needs to be improved.


Target Population and Need

Sleep and rest is an important part of one's daily cycle in order to ensure that one's mind and body is fully rested and rejuvenated. During sleep, the body needs to repair muscle, consolidate memory, and release hormones. Teens need at least eight hours of sleep in order to ensure that all of these functions can be executed. Often times, teens and adults are unable to sleep through entire cycles or do not sleep for the recommended amount of time due to stress, other time consuming activities, or problems with sleeping. Circadian Sleepwear is a beanie with sensors embedded in it that works in conjunction with app in order to track sleep cycles to recommend times for the user to fall asleep and wake up for enough sleep and to awake well-rested. The device itself influences brain waves in order to make falling asleep easier and waking up gentler. When it is time to sleep, the device will slow brain waves to prepare the body for sleep, and will readjust accordingly to the user's sleep cycles. The app will also allow the user to look back on the sleep cycles of previous nights as well as average sleep statistics. It also functions as an alarm to awake the user at the end of a sleep cycle.

The target population for this device those that have problems sleeping, especially those that have difficulty getting a full night's rest. The demographic would be those aged 18-40, under stress and/or concerned with activities involving school and/or work that want to be able to fall asleep easier.

Problem Understanding Form


Device Design

Brainlogo.jpg Beanie.jpg

Inferential Statistics

Sleep Cycles

In an experiment to decide the validity of the device in its analysis of one's sleep cycles, three subjects' sleep cycles were examined using the Circadian Sleepwear device and using the results of an EEG, or electroencephalography. The cycles determined by the EEG were used as the gold standard.


Descriptive Statistics

Circadian Sleepwear Mean: 100.333 minutes
Circadian Sleepwear Standard Deviation: 12.462 minutes

Gold Standard Mean: 99.833 minutes
Gold Standard Standard Deviation: 10.826 minutes

Because there are two groups of values being compared here, a paired t-test will be used in order to compare the two groups. A t-test is used because there are two groups and it is paired, because each of the values corresponds to the same cycle being recorded by the two methods. After conducting the t-test, the t value found was to be 0.8985. Because this value is much greater than the alpha of 0.05, it can be concluded that there is no statistically significant difference between the two data sets.


Here is the graph illustrating the mean length of sleep cycles as recorded by the Circadian Sleepwear device and the gold standard.


Here is the scatter plot with the trend line, displaying the correlation between the lengths of cycles for the Circadian Sleepwear device and the gold standard device.


Using the Pearson R-value of 0.91344, it can be understood that there is a positive correlation between the values found by our device, Circadian Sleepwear, and the gold standard. This R-value close to one signifies that the two values are correlated, indicating that there is some accuracy to the sleep cycles found by our device.