Shampoo Experiment Part 2

Here we go... lets get right to it since I know you all are so excited to see the results!

In the last post we discussed my variables, controls, hypothesis, and DOE/methods so we're ready for:

PROCEDURE!

We covered much of this in the previous sections, so I'm just going to do a quick summary. For each set of test variables (line) in the DOE, the procedure was the following:

1) On day before testing each set of conditions, run "Control 1"
    - Shower between 11am and 12pm
    - Get hair wet
    - Use all products (shampoo, conditioner, leave-in conditioner)
    - Leave hair down to dry as quickly as possible
2) The following morning, around 7am, perform the odor test
    - Smell top of  head and give rating
    - Smell right armpit and give rating
3) Just prior to next shower, rate dirtiness and record all data (if not yet recorded for odor test.)
4) On test day, shower between 11am and 12pm. Use test conditions shown in DOE for that day.
5) The following morning, around 7am, perform odor test
    - Smell top of head and give rating
    - Smell right armpit and give rating
6) Just prior to next shower (between 11am and 12pm) rate dirtiness and record data.

As you can see, my procedure is quite simple. Shower every day around the same time, rate odor and dirtiness around the same time each day, follow the test conditions in the DOE.


RESULTS!

Now, what you've all been waiting for... the results!

First, lets look at armpit smell:

Scale:

1 = No unusual/bad smell

5 = Worst smell imaginable

Average armpit smell with shampoo = 1.86

Average armpit smell without shampoo = 1.09

Next, Head Smell:

Scale:

1 = No unusual/bad smell

5 = Worst smell imaginable

Average head smell with shampoo = 1.29

Average head smell without shampoo = 2.25

And, with a little more test conditions detail:

Finally, dirtiness rating:

Scale:

1 = Same as full shower (control 1)

5 = Same as no shower (control 2)

Average dirtiness rating with shampoo = 1.38

Average dirtiness rating without shampoo = 2.55

And, with more detail:

And there you have it! The results!

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What? Disappointed? I have reported my results. I think what you were really looking for is:

CONCLUSIONS!

So, what does it all mean? There are some interesting things to note in my data.

First, lets get armpit smell out of the way. I was looking for a way to check my level of "overall dirtiness" other than my self rating of how I felt. I decided that armpit smell might be a way to do this. However, you can see by looking at the data that there is NO correlation between armpit smell and the use of shampoo or how clean I felt. Just to make that perfectly clear, here are some scatter plots:

Same as above. No correlation between armpit smell and use of shampoo. Or really, some suggestion of an inverse relationship where using shampoo makes my armpits smell worse. 

Compared to Dirtiness rating:

And, compared to head smell:

I did not take the time to add R squared values to these scatter plots. but I think its pretty clear that there is no correlation worth discussing here. We can eliminate armpit smell from the rest of our discussion.

And, onto some interesting data in my dirtiness ratings:

Check out this graph again:

There are a few key things to note here:

1) Look at the first (blue) bar. That is the bar for the average of "Control 1." If you recall my scales above, a rating of "1" is defined as "the same as Control 1." Therefore, all of the dirtiness ratings for "Control 1" days SHOULD be a rating of "1." But, the average is greater than one. There were 3 days in my experiment where I rated a "Control 1" day a rating of "2." 

My conclusion here is that because I was actively considering how "dirty" I felt, I was more likely to feel "dirty" and even days where I took a full shower I sometimes felt a little less than clean. This is one of the indications that this subjective rating is not the best metric to use.

2) Look at the last (also blue) bar. This is no shower. Again, by my own definition of my rating scale this should be a 5 but it is a 4. I didn't feel as "dirty" as I have in the past. 

3) Look at the second to last (dark red) bar. This is my "baseline 2" and the condition that started the whole experiment. I had anecdotally noticed that on days where I used the conditions in "baseline 2" I felt "as dirty" as if I took no shower at all. Here, my own self-rating of dirtiness does not support this initial evidence.

For notes 2 and 3 above here is my conclusion:

As the experiment progressed, I got more "used" to non-shampoo days and days where I did not even get my hair wet. There were a few times that I ran a dry-hair day that we did not rate and it had to be repeated. By the time I got to the dry-hair days that we did rate, I was more used to skipping my hair entirely and rated them lower. If a replication of this experiment is done, I suggest that these conditions be tested both early and late in the experiment and compare them. 

4) Use of dry shampoo had little to no effect on how "dirty" I felt. The experimenter noticed that scalp/hair appeared a little less dirty visually, but this evidence was not documented properly.

There are still some general trends that we can pull out of this data. However, based on above, these should be taken lightly as the results are likely biased by many uncontrollable factors that have previously been discussed.

Here we see the trend more clearly:

What we see here is:

1) Shampoo does have some effect (the jump from the blue bar to the red bar is elimination of shampoo)

2) Leave-In conditioner has no effect (the lack of jump between the red and orange/yellow bar shows the elimination of leave-in conditioner has no effect.)

3) Use of water has the largest effect (the jump between the orange/yellow bar and the green bar is the elimination of water.) 

So, based on my self ratings, the best way to feel "clean" each day is to get my hair wet.

Finally, Head Smell Conclusions. Lets look at that bar graph again:

1) Look at the first blue bar compared to the next three (red, orange/yellow, and green) bars. Shampoo does not have a significant effect on head smell.

2) Look at the first 4 bars clumped together and compare that to the remaining 6 bars clumped. The first 4 include leave-in conditioner and the remaining 6 do not. 

3) Scalp scrub seems to have a negative effect. Compare orange/yellow bar to green bar, eliminating scalp scrub MAYBE reduces smell slightly on wet hair. It seems to have a larger effect on dry hair. Compare the pink bar to the dark red bar. Eliminating scalp scrub (dark red) increases odor rating. More data is needed to make a solid conclusion on scalp scrub.

4) Again we see little effect from dry shampoo (compare pink bar and light green bar next to it.)

And again, we can pull some overall trends from this data. Here is a summary:

1) Shampoo has basically no effect on head smell. (Compare blue and red bars.)

2) Leave in conditioner has a significant effect (compare red bar to orange/yellow bar.)

3) An interesting drop in smell ratings when hair did not get wet (compare orange/yellow bar to the green bar.) My conclusion here is that getting my hair wet actually washes away the previous day's leave in conditioner. On days when I did not get my hair wet, the smell of the the previous day's leave in conditioner was still present enough to give a smell rating in between a day when leave-in conditioner was used (red) and a day when I wet my hair but did not use leave in conditioner (orange/yellow.)

4) The data confirms that skipping a shower completely does give a higher smell rating than any of the test conditions.

And, one final conclusion is that the experimenter has no idea what color that one bar is. Is it orange? Is it yellow? Perhaps marigold. Leave a comment and tell me what color you think it is.

So, there you have it. A quick summary of what we have learned:

1) This experiment was full of bias and much more repetition is needed to draw solid scientific conclusions from it.

2) The initial conclusions (that should be validated by other experiments) are the following:

   - The biggest factor on "dirtiness" is whether or not hair got wet.

   - The biggest factor on "head smell" is use of Leave-in conditioner. 

   - Armpit smell had no correlation to this experiment and future validation of this work does not need to include this data.

NEXT WEEK!

Next week I will milk a 3rd post out of this one experiment by covering the following:

  - Why I still don't know WHY and the Day 30 Extra Trail.*

  - Do women's menstrual cycles actually mess up the data?

*Yes, I promised these topics would occur "next week" last week which means that they should be included in this post. However, this post is already quite long so I have decided to do a Part 3 to the Shampoo Experiment posts. Sorry. I'm in charge and I can change things. At least I delivered on the graph promise. 

  

Merry Christmas!

The Tap Dancing Engineer will be spending most of this Wednesday visiting family in a home with no internet. I will attempt to post today's update but it will most likely be very late and may not happen until tomorrow. In the future, barring things like Christmas, I plan to post every Wednesday.

Happy Holidays to all. I shall soon bring you gifts of graphs!

-TDE

Welcome + The Shampoo Experiment Part 1

Hi! I'd like to thank last week's vole for getting me started on this blog, and I'd like to welcome all of you to my blog. Here is where I will post interesting things. In general, they will be somehow related to STEM or tap dance. One thing I really want to blog about is how I apply math and science to mundane daily life. First of all, I think its interesting. Second, it shows ways that math and science are useful to everyone and useful for non-science things. I also plan to post about critical thinking and problem solving. Critical thinking is basically just applying science-like thinking to everything so it should fit in well with my posts about the application of science. And of course, there will be tap dance.

Now, onto my first experiment!

The Shampoo Experiment Part 1: Design of Experiment

A little while ago I was sitting on my couch feeling like I really needed a shower. Yep, feelin dirty. But I had already taken a shower that day. And no, I had not done any tap dancing after my shower. Shocking, but true. I found myself once again noticing that if I took a shower without washing my hair I felt almost as "dirty" as if I had taken no shower at all. The interesting part about this is that I often skip shampoo* when I shower. On those days I don't feel dirty. In fact, it seems no different than the days that I use shampoo.

*Did you know that it's better if you don't use shampoo every day? This is especially true for curly hair that gets extra frizzy when it gets dried out. Natural oils are good for your hair. Some people never use shampoo at all. These people call their movement "no poo." They really should have ran that past a few more people before deciding on a name. Its real. Google it. 

So, I found myself realizing/confirming that if I don't do anything to my hair I feel dirty, and if I get it wet and use conditioner I feel clean. I wanted to know why. Or, if not exactly why*, then exactly what was the main causal factor.

*Note: We often get think we've discovered "why" something happens but we really haven't truly figured out the why. There's this surprisingly confusing fuzzy area between narrowing down to the main factor and truly understanding the full mechanism of why. More on this later.

Clearly the only thing to do in this situation is to design an experiment to test all possible factors!

I started by listing out the possible factors (variables):
- Water
- Conditioner
- Scalp Scrub (when I use conditioner I work it through my hair and therefore indirectly "scrub" my scalp in the process.)

My research on the No Poo movement (seriously, Google it) led me to add dry shampoo as another aspect of my experiment. And, after the first couple of days of my experiment I realized I had another factor, my leave in conditioner.

The final list of possible factors:
- Water
- Conditioner
- Scalp Scrub
- Leave In Conditioner
(Plus dry shampoo as an extra test to see if it could make me feel less dirty on dry hair days.)

Hypothesis!

To be honest, I never wrote down a clear hypothesis statement. Going into this my guess (hypothesis) was that it was either the use of water or the scalp scrub (or most likely the combination of the two) that would be the main cause of my dirty feeling.

So, if I were to write it now for what I was thinking then, it would be something like this:

Hypothesis: Getting my hair wet and massaging/scrubbing the scalp causes me to feel clean.

Controls!

Here are things I did to try to have scientific controls in my experiment:
1) Take a shower at approximately the same time every day. This didn't always happen, but I did my best to stick to it and feel it was acceptably controlled.
2) Try to keep level of exercise/sweat consistent each day. This was harder, but mostly successful. There were some tap dance days and lots of packing and moving boxes as we were in the process of moving. So I tended to get a little warm/sweaty every day but not a lot. The day that I tap danced ALL day and got really sweaty was not included in my data.
3) Leave my hair down after showers as much as possible so that it dries in approximately the same length of time each day. (It was long at the time and I often pulled it up to keep it out of my way.)
4) Collect data at approximately the same time every day.
5) Brush my hair the same amount each day (to avoid extra "scalp scrub" factors.)
6) Wear white cotton undies every day (to prevent any outside contributions to feminine itch or discomfort that could have skewed my dirtiness ratings.)*
7) Include data from a blind experimenter. (More below.)
8) Take a full shower, including shampoo, every other day to "reset" for the next set of experimental conditions.

*In the name of science and thorough explanations of science, I am sharing everything. And ladies, there is no shame in admitting that part of what makes us feel we need a shower is feminine discomfort. 

Concerns!

There were more of these than I'd like there to be. As explained above, I tried to include as many controls as possible but this is still a VERY subjective experiment. Here are things I had concerns about in terms of eliminating bias.
1) Not double blind and impossible to be double blind.
1a) I was acting as both the lead experimenter and the only test subject. This is not good science.
1b) The testing involved physically doing things to the test subject (me) such that it is impossible for the test subject to be blind. This is the worst case scientifically as there is no way to eliminate bias from the test subject.
1c) Given 1a and 1b, there was no way for the lead experimenter to be blind. Logical deduction: The test subject (me) and the experimenter (also me) were the same person, and the test subject could not be blind, therefore it follows that the experimenter could not be blind.

2) Data collected is subjective. I self-rated on a 1-5 scale of dirtiness (where 1 is the same as a full shower and 5 is the same as no shower.) Add to that the fact that there was no way to eliminate bias via blind trials and we have a recipe for really bad science.

To help with these concerns I implemented a second set of data after the first 2 days of my experiment. (I later re-ran the first 2 trial sets and ignored the initial dirtiness results in order to have complete data on everything.) In addition to my self rating of "dirtiness" I added a second experimenter who rated odor of the top of my head and odor of my armpit each day. This experimenter was blind. However, smell rating (also a 1-5 scale, where 1 is no bad smell and 5 is really bad smell) is still subjective and we are still far from an ideal experiment.

n!
(not factorial, I'm just excited about science)
In a scientific experiment, "n" refers to the number of times you repeat the same experimental conditions. The lowest this number should ever be is 3.* In my experiment, n=1. The reason for this is time. I could only test a new set of variables every other day. My secondary experimenter wasn't thrilled with the idea of smelling me every day for any length of time, and especially not interested in doing this for months. Even with n=1, my experiment took 30 days. That was long enough. Please note that n=1 is really REALLY bad science.

*n=3 is acceptable for middle school science projects. It is also commonly used in industry for failure prediction and analysis (as opposed to research.) This is because someone already did the research to develop a test method that you are following. Using n=3 should be able to confirm if your product meets your test method or not. n=3 also works for confirmation of contamination as many people previously did a whole lot of research to develop equipment to identify material composition accurately enough that n=3 is OK for CSI. For research, ideally you should target n=5 for a respectable experiment. If you're looking to publish in a scientific journal then n should equal A LOT. 

So, we've established my variables, my hypothesis, my controls, and my concerns. We've also established that this was a really poor experiment in terms of bias control.

DOE!

Now, the meat of it. The DOE!

I set up my DOE such that I changed only 1 variable at a time. There were a few situations that were impossible however. Mostly, the use of conditioner (regular or leave in) on dry hair. I tested these indirectly by doing a set of trials: wet hair/conditioner/leave in, wet hair/conditioner/no leave in, wet hair/no conditioner/leave in, and wet hair/no conditioner/no leave in. When everything was done, I ended up with the following table of trials:

Definitions:
Control 1 = Full shower with Shampoo

Control 2 = No shower at all

Baseline/Conditioner = Everything but shampoo (which I anecdotally noticed seems the same as Control 1.)

Baseline 2 = Body shower without getting hair wet or doing anything else to hair (which I anecdotally noticed seems the same as Control 2.)

Additional Info:
1) The red highlighted days are when I had my period*
2) The yellow highlighted days I was a bit sick.
3) Days 1 and 2 were ignored as they did not include smell data. Day 1 reoccured numerous times (every other day) and Day 2 reoccured on Day 19.
4) No ratings were done on Fridays. This is because my secondary experimenter and I often do not sleep in the same place on Thurs nights and therefore there was no ability to take smell data on Friday mornings. (This is why a second "control 1" is sometimes seen on Thurs)
5) I did the same trial on Day 11 and Day 13. Not on purpose. Got the same results though so thats promising for repetition.
6) If you're looking carefully you'll see some additional repetition. For example, Control 2 is shown on Day 17 and Day 19. We missed a few days. Or, it was so late in the day by the time we remembered that I decided to skip that day and redo it.
7) Day 30 was an extra test that I added based on my data up until then. We'll talk more about that later!

*Did you know that until very recently NO clinical research experiments were conducted on women, especially women of childbearing age, because everyone thought that our menstrual cycles would mess everything up? Or, they were concerned that the women in the experiments might be pregnant and did not want to endanger the unborn. Or who really knows why. This means that nearly ALL medical knowledge has not been adequately confirmed on women. We are now learning that women's experience of heart disease is very different than men's and that women react differently to many medications (both effectiveness and side effects.) Its pretty scary stuff, especially when you read that women were not really added to clinical research trials until the 1990s (!!!) and that even today they are still not well represented in clinical trials, especially phase 1 trials. Here is a short and readable summary. Here is the 1993 FDA publication that started to create true change. Here is is a more readable summary of that 1993 publication on the FDA website. And here is a 2008 paper discussing how women were still under-represented. 

If you find this interesting and you are an ADULT I highly recommend this book. Not safe for prudes!*

*Did I just add a footnote to my footnote? Yep. Prudes are cool! You be prudish if you are. Be you. But, if you are prudish, don't read that book. That is all.

A final note. I shall do my best to back up claims with either data or reputable publications. You should too. Don't believe everything you see on Facebook. :)



Stay tuned! Next week I'll briefly summarize my procedures, and present my results and conclusions! There are graphs! Yay! Graphs!

Also to be covered next week:
- That fuzzy area between the main factor and the mechanism of why
- Day 30 extra trial. Fun!

Peace and rhythm to you all,

         The Tap Dancing Engineer

While I figure out exactly what this blog will be....

Hi! I'm still working out the exact details of what this blog will be and I'm really not ready to post my official first entry. However, something happened yesterday that absolutely REQUIRES a photo-story and I thought I'd make use of my shiny new blog to tell it.



So, I left my apartment and walked out to the parking lot. There it was right in front of my building. A beautiful work of art in the snow.

Its like tiny little crop circles... but they're snow circles.

I thought perhaps an artistic kid in the apartment complex made it. But subconsciously I knew that wasn't the case. I knew that this wasn't made by a human. Later on it dawned on me that there were no footprints or any other sign of humans nearby. But at first I sat there pondering it. What WAS it? I looked for the beginning and the end of the snow doodle.

And there, right where it stopped was a largish dark rock. It actually looked a lot like a piece of coal. At this point my conscious brain still thought it was done by a child or maybe even an adult. I stared at it a bit admiring it. But then my subconscious smacked me out of my daydreaming and said "Thats not a lump of coal! Even though its seasonally appropriate, why would some kid be drawing with a lump of coal in the parking lot you fool!"

So, I thought "I'll show you." And I was winding up give that lump of coal a little kick across the parking lot when IT MOVED!

And then it kept moving. Round and round in frantic little circles.

I watched it for a while, trying to figure out what on earth was going on.

Then I took more pictures. And a short video.

At this point I'm thinking "ummm go home vole! You're drunk!"

And then he did a pathetic little tumbling summersault, righted himself, and stopped to rest. I could see his whole body heaving in an out with his breathing and I swear I could see his frantic little heartbeat. 

The poor little guy wound up in the parking lot somehow and was trying to borrow back underground. He was desperately searching for some soft ground but stuck on asphalt.  I didn't see a clear trail of how he got TO this spot in the parking lot. Maybe it was covered by the snow that fell while he was running in circles. Or, maybe he had narrowly escaped a hawk or owl or other predator that dropped him there. Whatever happened, he was NOT happy.

He was also in the middle of the parking lot, which is a pretty bad place to be if you're a vole. 

Here's the best picture I could get of him:

I tried to shoo him out of the parking lot but he was just so distraught and confused and scared that he couldn't even run from me. I probably could have just picked him up. I had my leather gloves on and considered it, but ran back to my apartment for a small box instead.

He climbed right into the box as if he knew he was being rescued. But, as I carried him to some nearby brush he seemed to have second thoughts about the whole thing. Perhaps being carried in a box feels a lot like being carried by a predator. He wasn't injured at all, just scared. I tried to get some pictures while he was in the box and easier to see, but then he started trying to escape. He did escape once, but we were still far from any sort of cover and the snow really wasn't deep enough on its own. So, back into the box he went and I took him closer to the cover of the nearby brush. 

I don't even know if he'll be able to dig into the frozen ground, but its gotta be better than running frantic little circles in the parking lot. I imagine there's a life lesson in this. Something about desperately circling in parking lots that rings true this time of year especially. So instead of frantically rushing around to finish your holiday shopping, try to take a moment to stop and enjoy time with your loved ones. Remember that the true holiday spirit has nothing to do with presents or shopping or parking lots. 

And, admire the beauty in the world. Step back and look at the bigger picture. See that art often stems from desperation. At least I think those are the lessons here. It truly was beautiful art... made by a vole.