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5.3 50 orange 35 blue 15 white marbles

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One hundred marbles. Students blind draw a single marble. Population probability is known. Tally the sample to obtain relative frequency.  Last spring the recommendation was to move to ratio level data . Upon further thought, the ratio level data would not demonstrate the linkage between mathematically determined probabilities and statistically inferred probabilities. Ratio level data wouldn't have obvious population values.  One could use the mass of the marbles to predict a known population mean, but that is a conceptually harder system in which to explain what the probability of individual mass classes ought to be. Those weight class probabilities would be driven by an underlying normal distribution. Students would not comprehend why the predicted probability for the class bounded by the mean minus a standard deviation and the mean has a predicted probability of 34% Fifty orange marbles, thirty-five blue marbles, and fifteen white marbles sets up an easier to se...
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Force of friction on a RipStik

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Trusty towed Ikaia while Trevor read the reading on the white spring scale in Newtons. Jerson and Finley walked alongside as safety officers, although Ikaia is very competent on the RipStik. Failure is always an option. The force remained the same, 15 Newtons, for both my 75 kg mass and Ikaia's 60 kg mass. This produces a slope of zero. The force of friction spring 2026 was 11 Newtons but this was the two-way average. Towing downhill requires more walking speed by the person towing and thus a higher speed for the rider. This is a less controlled situation than the slight uphill, so this was not attempted. 
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Kinetic friction

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Laboratory five focused on the force of kinetic friction.  Preset was laid out between 8:00 and 8:16 The large class and dearth of slot weights, coupled with an inability to easily order replacement weights, has each group working with four unique weights. With permutations and combinatorics, this provides ten data points. Data sheets were preprinted this term. No mass balances were brought to the laboratory: the sled is treated as zero when unloaded. This generates a y-intercept for all of the groups and thus a y=mx+b regression equation for the first time this term. This also makes the weight calculations much easier.  The morning notes were brief and light. After the 8:00 section the coefficients of friction were posted to the board.  Four weight rigs were set up on the outer tables using primarily green spring scales (500 gram-force max).  The center table was set up with two grit rigs and blue spring sc...
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Pwunso gymnosperms spice trees timber

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A walk of the front garden found a new tree had sprouted. The glove tree is the global source of all gloves.  The bus arrived just after 15:53. The size of the class this term, 29 students on the field trip, caused the roll call to be done as a single instance at the end of the walk.  The Ficus prolixa still seems to take too long for the marginal benefit. Tightening this up might help. A student noted that the aerial roots can be pounded and then used in a herbal steam bath to treat joint pain.  By 16:01 the class was at the clove trees. No cloves. Again. Kelarimalyanne, Lisarita, Sueleen, and Marikai in the lead.  At 16:07 the class was headed from the Araucaria columnaris to the Cinnamomum verum. The cinnamon tree is always in season. Delaura at the cinnamon tree, Marco behind her to the left. This is one the largest, if not largest, enrollments for this class to date. The class tends to spre...
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