Activity for tommi
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Comment | Post #292071 |
Does this have a systematic effect on hypothesis testing, as per the question? (more) |
— | 4 months ago |
| Edit | Post #291333 |
Post edited: |
— | 8 months ago |
| Edit | Post #291333 | Initial revision | — | 8 months ago |
| Question | — |
The effect of measurement accuracy and rounding on hypothesis testing I am checking the temperature I have at home with accuracy of one tenth of a grade (Celsius). The easily publicly available information is temperature in grades, with no decimals. I am doing very basic hypothesis testing: My null hypothesis is that temperatures I measure do not have a systematic b... (more) |
— | 8 months ago |
| Comment | Post #291012 |
Please wait for a while (some days) before cross-posting and link to the previous question in the question body. (more) |
— | 10 months ago |
| Comment | Post #290576 |
Please add that as (a part of) your answer. (more) |
— | 11 months ago |
| Edit | Post #290576 | Initial revision | — | 11 months ago |
| Question | — |
The derivatives of a function at a boundary point I have a function $f \colon [0, L[ \, \to \mathbb{R}$ and I want to use the derivatives of arbitrary high orders of this function at zero. The function is defined on the half-open interval $[0, L[ \, \ni 0$, for an $L >0$. Typically the derivative is only defined on interior points of an interval ... (more) |
— | 11 months ago |
| Edit | Post #290160 | Initial revision | — | about 1 year ago |
| Answer | — |
A: $\left(\forall \varepsilon >0: |a-b| < \varepsilon\right) \iff a=b$ vs. $\left(\forall \varepsilon > 0: a \le b + \varepsilon \right) \iff a \le b$ The absolute value version is equivalent to having both $a b - \varepsilon$, both for all positive epsilons. To see this, use the definition of the absolute value. Also, $a 0$ and $a \le b + \varepsilon$ for all $\varepsilon > 0$ are equivalent. Clearly the strict version implies the non-strict ... (more) |
— | about 1 year ago |
| Edit | Post #289973 | Initial revision | — | about 1 year ago |
| Answer | — |
A: Is mathematical pedagogy in scope? A lot of didactics is quite mathematical, but a lot is also far from it. Stuff like different ways of understanding division or Janvier-table of transformations between different representations of functions would, to me, feel at home, while something like TPACK-model of teacher knowledge or gende... (more) |
— | about 1 year ago |
| Comment | Post #289826 |
As a mathematician, my first instinct is to suggest that if there is only one or two candidates or only one or two voters, the probability for someone to get at least half the votes is quite large. Any formula should be consistent with this. (more) |
— | about 1 year ago |
| Edit | Post #289537 | Initial revision | — | over 1 year ago |
| Answer | — |
A: How can I choose a point from a uniform distribution within a regular polygon? A (regular, convex and some weaker condition would be sufficient) polygon is a finite union of triangles with one vertex at the origin, and which only meet at their edges. (I am being ambiguous whether I consider the triangles as closed or open, but this almost surely does not make a difference.) ... (more) |
— | over 1 year ago |
| Comment | Post #289495 |
Did visualizing the n = 2 case help you or your students? (more) |
— | over 1 year ago |
| Comment | Post #289007 |
You have some issues with which texts are in italics. Just a heads-up. (more) |
— | over 1 year ago |
| Edit | Post #288280 |
Post edited: |
— | over 1 year ago |
| Comment | Post #288280 |
Good point. Maybe using the word "or" is warranted there. (more) |
— | over 1 year ago |
| Edit | Post #288280 | Initial revision | — | over 1 year ago |
| Answer | — |
A: how to mathematically express a relationship in which a vector can be any 3D unit vector If I understand the situation correctly, the problematic issue is the zero rotation, and the issue is that if you do not rotate things at all, than that corresponds to a zero rotation around any axis. If this is true, then I could understand any of your three ideas. The third one might be marginal... (more) |
— | over 1 year ago |
| Edit | Post #288200 | Initial revision | — | over 1 year ago |
| Answer | — |
A: How to compare lotteries, when one has highest probability of winning the jackpot, but another the highest Expected Value? To understand what is happening, consider smaller and simpler numbers. Consider a first lottery with 1/100 chance of winning 10 units, and thereby an expected value of 1/10. Then consider a second lottery with 1/1000 chance of winning 100 units. The expected value is still 1/10, even though the... (more) |
— | over 1 year ago |
| Edit | Post #288114 | Initial revision | — | over 1 year ago |
| Answer | — |
A: 2 construals "of 100 patients presenting with a lump like the claimant’s in Gregg v Scott, 42 will be ‘cured’ if they are treated immediately." One can try to make the arguments mathematically more precise. The first claim is that each patient has a 42 % chance of being cured with the treatment. The second claim is saying there is a genetic factor that 42 % of people have, such that the conditional probability of being cured given the fa... (more) |
— | over 1 year ago |
| Edit | Post #287974 |
Post edited: |
— | almost 2 years ago |
| Edit | Post #287974 | Initial revision | — | almost 2 years ago |
| Question | — |
The meaning of $\pm$ Consider the claim $ |x| = \pm x $. I would interpret it as stating that $|x| = x$ and $|x| = -x$, thereby implying that $x = 0$. A user at Matheducators stackexchange interprets it as saying that $|x| = x$ or $|x| = -x$, which holds for all real numbers. I would typically use the notation ... (more) |
— | almost 2 years ago |
| Edit | Post #287916 | Initial revision | — | almost 2 years ago |
| Question | — |
Connection between caustics and conjugate points? Conjugate points on manifolds are, roughly speaking, points which are connected by a multitude of geodesics, so that there are problems with uniqueness of the shortest path between the points. In symplectic geometry there is the concept of caustics, https://en.wikipedia.org/wiki/Caustic(mathematic... (more) |
— | almost 2 years ago |
| Edit | Post #287419 |
Post edited: clarified the question based on the comments and added the probability tag |
— | almost 2 years ago |
| Suggested Edit | Post #287419 |
Suggested edit: clarified the question based on the comments and added the probability tag (more) |
helpful | about 2 years ago |
| Comment | Post #287419 |
Could you define more formally in the question how the points are distributed? A continuous distribution within a fixed square would presumably lead to probability zero for any given length, as there would be uncountably with possible lengths. (This is not a proper argument, just a guess.) (more) |
— | about 2 years ago |
| Edit | Post #286853 | Initial revision | — | over 2 years ago |
| Answer | — |
A: Is there a way to encode a unique arrangement of vertices of a graph with a unique short word? As mentioned in a comment, you seem to wish to classify sets of points, not graphs as such. If you wish to classify them bijectively with word, you need the cardinalities of the sets to match; that is, there must be the same amount of possible word and the same about of possible sets of points. ... (more) |
— | over 2 years ago |
| Edit | Post #286810 | Initial revision | — | over 2 years ago |
| Answer | — |
A: What's the common ratio for this geometric sequence? If you look at the first sequence and divide every term by 14, you get a much simpler sequence. Consider how you could find the ratio from this and try the method on the second sequence. Further solution/hint You can divide by the first term in the second sequence, too. What remains is essen... (more) |
— | over 2 years ago |
| Edit | Post #286710 | Initial revision | — | over 2 years ago |
| Answer | — |
A: What are the 2 arithmetic means of $x + y$ and $4x - 2y$? This problems seems to be missing information, or alternatively it is simple. Means here seems to be the difference between consecutive terms of an arithmetic sequence. Thus, the answer in the first exercise consists of the numbers 10+15, 10+25, 10+35, ..., 40-25, 40-15. That is, you start from th... (more) |
— | over 2 years ago |
| Comment | Post #286709 |
I have not seen this use of «mean» before, but maybe it is used somewhere. The world is a big place. (more) |
— | over 2 years ago |
| Edit | Post #286527 | Initial revision | — | over 2 years ago |
| Question | — |
Notation for one-sided hypothesis testing I see the following notation for one-sided hypothesis testing: $H0$: $K = 2$ $H1$: $K > 2$ I would find it more natural to write: $H0$: $K \le 2$ $H1$: $K > 2$ Assume a situation where $K$ is not, by definition, limited to equal or be higher than two. $K$ is just a dummy variable an... (more) |
— | over 2 years ago |
| Comment | Post #285977 |
You have $T$ as $m \times n$, while both $x$ and $y$ and $n$-vectors. Might want to fix that. (more) |
— | almost 3 years ago |
| Edit | Post #285763 | Initial revision | — | almost 3 years ago |
| Answer | — |
A: Missing a solution: Are A and B always equal if A-B=0 One way to think about the question is that you get $$ (4x-12)(5-x) = 0. $$ A product $ab$ is zero if and only if $a = 0$ or $b = 0$. So you get either $4x=12$ or $5=x$, thus getting your two solutions. No division required. (more) |
— | almost 3 years ago |
| Comment | Post #285670 |
Okay, but have you done yourself to create the understanding? Have you calculated with some examples, created visual representations, etc. of relevant problems? (more) |
— | almost 3 years ago |
| Comment | Post #285670 |
How have you tried to understand this and what kind of results has it given you thus far? (more) |
— | almost 3 years ago |
| Comment | Post #285443 |
This will help people in answering you, since it gives an idea of your abilities and may reveal potential misunderstandings. Writing it down also forces you to think about the problem and, with luck, might even end up in your solving it. (more) |
— | almost 3 years ago |
| Edit | Post #285348 | Initial revision | — | about 3 years ago |
| Answer | — |
A: How can you analogize mathematical induction to dominoes falling, if some domino can fail to topple? It is an analogy and the essential point is that each step leads to the next, just like, in case of dominoes (when they work), each one topples the next. You have focused upon a case where the analogy breaks. It is a good idea to detect such cases and maybe it makes the analogy less useful for you... (more) |
— | about 3 years ago |