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Showing posts from March, 2024

11.3 An attempt at Cohen's d effect size with hula hooping

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For section 11.3 on Cohen's d effect size I wanted an in class activity that would generate a statistically significant difference. Based on prior interactions with students and hoops, I was accustomed to students not knowing how to hoop. The basic concept was have them try to hoop, essentially not do well, show them how to hoop, and then use a paired t-test for a difference in the number of rotations from before to after. There were two complications with this plan. The first was a very small sample size. The second was that some students already knew how to hoop. Such as Jessian above. The result was a p-value larger than our alpha of 0.05. That's a paired t-test for a pairwise difference in means - a "type 1" TTEST in Google Sheets. While the Cohen's d should not have proceeded, I still wanted to demonstrate the functions. Obviously there are a plethora of problems with this example - Jessian clearly knew how to hoop and could have done more but had

Colors of light

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Monday started with the Limits of Light video from Austria. Wednesday tackled the rainbow and scientific fact versus belief. That could use a lighter touch and some new directions. I still would like to have a modern spectrum tube rig. Thursday the yellow towel was hard to focus on, so I switched to Sphagneticola trilobata. Focus was still a problem, but it still illustrrated real yellow versus fake yellow. This term I forgot to pre-position the microscope in A101 the day before.  The circle on the right was made with yarn and a marker, the angles were constructed.  At the end of class. This lab still goes well and allows a new approach to Desmos. 

Botany lab eleven: invasive species

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 The class opened with a new invasive species playlist that ran for forty minutes until 11:40.  Watching the invasive species playlist. Then I gave a presentation on invasive species of plants on Pohnpei.  This included referencing the iNaturalist presentation on how to mark an observation as invasive in iNaturalist desktop. The assignment was for the students to return to where they live and make observations of invasives around their place of residence: This laboratory focuses on having you look around where you are staying and observing potential invasive plants around where you live. Look for any plants that appear to an invasive species, especially ones that could be a new-to-Pohnpei invasive plant. Make three observations of three different plants that appear to be invasive using iNaturalist. In the notes record whether the invasive plant has a use or is useless, whether the invasive plant appears to be aggressive or not aggressive, and whether the invasive appears to be shade

11.2 t-test for a difference of independent sample means

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I had conceived of using hula hoops with a goal of recording the number of rotations attainable in a minute. After data would have been gathered, a study of whether a gender difference exists for hooping would have been run. A hidden variable experiment of a sort. But the El Niño spring dry weather returned with brilliant sunshine. The weather convinced me to rerun the paper aircraft experiment using the darts. The real variable, however, was the absence of wind. That absence plus the darts distance capabilities ensured a strongly significant difference.  The second floor balcony from which the aircraft are launched. Klara, Vincent, Jeffrin, and Kenygie. The p-value was surprising. The effect size is very large with a Cohen's d value of 1.43

Floral morphology

Despite this being an El Niño spring, the weather was rainy into midafternoon. With another outdoor walk scheduled for Thursday, and spring break next week, there was no option to swap a floral walk with an indoor activity. During the video playlist  the weather went sunny. After the flower shop video I did a board diagram of a flower to reinforce the whorl part names. Then the class went on a very short walk to view Gardenia taitensis, Jasminum sambac, Ixora coccinea, Turnera ulmifolia, and Hymenocallis littoralis. The walk ended at the learning resource center. No photos were taken, none were given. 

11.1 Paired t-test for a pairwise difference of means

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Attendance has been sketchy. Facing a very small sample I opted to partially rig the paired marbles t-test exercise. In the past students have randomly selected marbles which had led to small differentials and ties where the two marbles are the same mass. This term I rigged the game. Marbles less than or equal to 4.8 grams on one side, marbles greater than or equal to 5.2 grams on the other side.  With seven students the p-value was not significant at an alpha of 0.05. Note that there was a near miss risk of 100% correct identifications. This suggests that exclusion of 4.9 and 5.1 gram marbles should not be done. A study of 45 differences of 0.1 grams either way produced a p-value of 0.00002. Using a chi-square test obtained a p-value of 0.0006. Students can detect differences as small as 0.1 grams. Of course, moving in a direction to make the call harder will result in a higher risk of failing to reject the null hypothesis, and in this demonstration the intent is to reject

Material culture presentations

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Ifancy: Pei ngar. Lihli pounder. Breadfruit pounder. Summer only rahk season. The other season is isol, which is the season for yam starting in the northern hemisphere fall.  Falemon: Ngarangar coconut shell  Hyisha: Ngarangar shot glass size developed prhaps for market use. Isaiah: Ngarangar Family friend. From Ahnd. Isaiah covered how the ngarangar is handled and to be passed. Lee Sandra: Yaas Woleiaian thatch  Shanellia: Woleaian teoriu (lavalava) used to ask for marriage, divorce, forgiveness Marstella: Giliipweopweo, sitting mat, Woleaian. Jasiree: Saipe (Mortlockese) Saipe. Created for sale. Pandanus. Jasery: Woleaian mwaremware Bennet: Pohnpeian nehn sukusuk. Only yam can be pounded with this. Jordan: tok from kosrae DeShawn: puhlet sracnu pwaht the individual serving

Speed of sound

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Rain invoked plan B: resonant tube measurements to obtain the speed of sound. Forgotten: meter sticks. Problematic: Power, water off. Pouring from erlenmeyer flask works, but is noisy.  I used a pipe to illustrate the modes. I gathered all student data onto the board.  Jazzlyn records data The 8:00 section wrapped up with a lecture on the implications of the negative branch of the hyperbola. The math says the negative branch exists, but in reality negative frequency has no clear meaning. 8:00 data Lilly Rose, Lisa Praise, and Daniel would work slowly and methodically, turning in the best results. Groups that went faster obtained worse results. The process of overfilling and then backing back down to the resonance worked well. Took more time, but generated better results. The use of flasks and beakers solved the false resonance off of the empty graduated cylinders.  Physical science can be fun? Joyleen,

Desmos geometry

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I never know quite what to do with the advances in mathematical tools, I just know that mathematics education stands at the edge of vast new technical capabilities. One of the tools I actively use, Desmos graphing calculator, has released a new version of their geometry calculator.  Desmos geometry Drag a purple dot on the graph to move the translation of the triangle around the graph. A more advanced demonstration is of maximizing the area inside a rectangle for a fixed perimeter done by Desmos. Maximize the area of a rectangle Drag the blue dot C until the maximum value for the area appears. How does that relate to the red coordinate displayed along the parabola? These tools open not only whole new ways to explore mathematics, these tools provide the capability to explore things that one could not previously explore. Such as an analysis of the conduction rate of water in celery xylem in a botany course laboratory. Celery conduction rate analysis But the students did not cut their cel

Thatching

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The weather began sunny clear, but the rain quickly chased us under the roof line. So much for the El Niño related drought.  Lee Sandra, Shanellia, Jarret Ritarsky, Gilbert, Bennet Bennet demonstrates skill in thatching.  Lee Sandra, Shanellia, Jasery Jarret makes rope with an assist from Lee Sandra. Nicely done thatch, and not the kind done in Woleai. Very fast to learn proficiency. 

Botany lab ten: soil analysis

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Laboratory used soil tests kits and a couple of probes to determine soil nitrogen, phosphorus, potassium, pH, and temperature.  Kits from LaMotte were used. Soil from my own yard suggests low nitrogen, high phosphorus, and perhaps no potassium. The pH would come in at 6.6. Large test tubes were needed for the roughly 30 ml extraction process. Perhaps small graduated cylinders would have helped get the amount right. A presentation included a copy of the instructions. Test tubes racks were also a necessary addition.  For the NPK tests the smaller test tubes used to mimic the one supplied by LaMotte were too full to mix. So capped test tubes were found and used.  Benselyn looks for a test tube of the appropriate size.  Spoons were disposable items. Timers were marginally useless. Students used their phones.  More test tablets will be needed for spring 2025.  Devron probably testing for potassi