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11.1 t-test for a paired difference in marble masses

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Students select two marbles from a box, one from each side of a divided box. One side includes marbles less than or equal to 5.2 grams, the other side contains marbles greater than 5.2 grams.  Data from spring 2026 demonstrated that students could distinguish which marble was more massive using a paired t-test and an alpha of 0.05. The ability of Desmos to display the t-distribution graphically (and calculate t-ciritical from data) allows for the graphical display of the result. The t-test capability displays the p-value based directly on the data. Desmos has become a powerful tool for displaying statistical results graphically. Calculating t-critical involves using tdist(n-1).inversecdf(0.975) for a 95% confidence interval. In the above example the test is an independent samples t-test, not a pairwise test of the differences.  Desmos To do a pairwise t-test the data has to be the pairwise differences, which can also be done as seen above.  Desmos This term ...

Rocks

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This laboratory has two separate goals.  To learn how rocks are characterized To learn to build a slide deck using mobile apps Questions to be explored in the laboratory: What are the three basic types of rocks? What is rock hardness? What is rock luster? What is rock breakage? What is rock color streak? What is the identification of your rock? On Pohnpei there are essentially two types of rocks. The black colored rock is basalt, a combination of minerals produced by the volcanic eruptions that formed the island. Basalt can be composed of different minerals. Basalt on Pohnpei contains iron which oxidizes to form red and brown colors. The red clay soils are also high in iron. There is so much iron in the ground that well water in some places has too much iron to be consumed by us. Out in Nett there is a special facility that removes iron from the well water. The other type of rock is coral, usually a white color. Coral is not a mineral because the origin of coral is in a living anim...

Desmos graphs t-distribution and calculates t-critical

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Desmos can now calculate t-critical values and graph the t-distribution, an upgrade from only being able to graph the normal distribution. Desmos The normal distribution showed area values larger than 0.95 when upper and lower bounds calculated using the t-distribution were entered. The availability of the t-distribution now shows the correct probability for upper and lower limits calculated using the t-distribution, a necessity when working with sample means. The function for generating t-critical for a sample size n and a 95% confidence interval: The period notation allows one to apply additional functions . These functions allow one to evaluate or manipulate the distribution in different ways. The Desmos file provides a visual approach to confidence interval hypothesis testing calculations done in Google Sheets . The above spreadsheet pulls data from exercises in chapter 9.2 and 10.1 of an MS 150 Statistics course. 

Healthy sexuality

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Unit eight on healthy sexuality has been problematic for the past two runs of the SC 101 Health Science course. The students would prefer to be gender separated for this unit but the course schedule doesn't have that flexibility.  There are cultural and traditional factors underneath the discomfort. These are cultures where on one island women who are having their monthly were once sent to a women's house away from the village during that period of time. These things are not only not talked about, in some cases they are hidden away to the maximum extent possible.  This term the realization landed that the overhead hook system provided a way to put up a movable curtain. Women on one side, men on the other.  Feedback was only anecdotal at the end of the two sessions.  That feedback was very positive, with both the men and women expressing appreciation for and comfort with the arrangement. Out of sight really is out of min...

10.1 Confidence interval hypothesis test

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  A confidence interval hypothesis test was done on the theory that the navel is located at the golden ratio, that the fibobelly ratio is the golden ratio.  Spreadsheet This was refuted for both the females and the males. The number line approach to interpreting confidence intervals was illustrated on the board. 10.2 and 10.3 then use the data from 9.2 and 10.1 (Paper aircraft flight distance and fibobelly data) in a single combined spreadsheet to illustrate the material in those two sections. The slide deck provides guidance and useful links.

9.2 Paper aircraft confidence interval

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This term the aircraft were thrown from the second floor of the east end of the A classroom building. Downstairs after measuring distances, Estele and Tiepo looking out over the field of paper aircraft. Setting up to measure those that went negative. West breeze, very light, El NiƱo induced. Can you see the plane?  Caught a brief surge in the west wind. Way out near the fence line. Board work Spreadsheet for current term. A multi-term master also exists.