Relation (mathematics) redirects here. For a more general notion of relation, see Finitary relation. For a more combinatorial viewpoint, see Theory of relations. In mathematics, a binary relation on a set A is a collection of ordered pairs of elements of A. In other words, it is a subset of the Cartesian product A2 = A × A. More generally, a binary relation between two sets A and B is a subset of A × B. The terms dyadic relation and 2-place relation are synonyms for binary relations.
Sunday, October 30, 2011
Saturday, October 29, 2011
Friday, October 28, 2011
Why Relations between Variables are Important
Why Relations between Variables are Important
Generally speaking, the ultimate goal of every research or scientific analysis is to find relations between variables. The philosophy of science teaches us that there is no other way of representing "meaning" except in terms of relations between some quantities or qualities; either way involves relations between variables. Thus, the advancement of science must always involve finding new relations between variables. Correlational research involves measuring such relations in the most straightforward manner. However, experimental research is not any different in this respect. For example, the above mentioned experiment comparing WCC in males and females can be described as looking for a correlation between two variables: Gender and WCC. Statistics does nothing else but help us evaluate relations between variables. Actually, all of the hundreds of procedures that are described in this online textbook can be interpreted in terms of evaluating various kinds of inter-variable relations.
How to Measure the Magnitude (Strength) of Relations between Variables
How to Measure the Magnitude (Strength) of Relations between Variables
- If all WCC scores of males were equal exactly to 100 and those of females equal to 102, then all deviations from the grand mean in our sample would be entirely accounted for by gender. We would say that in our sample, Gender is perfectly correlated with WCC, that is, 100% of the observed differences between subjects regarding their WCC is accounted for by their gender.
- If WCC scores were in the range of 0-1000, the same difference (of 2) between the average WCC of males and females found in the study would account for such a small part of the overall differentiation of scores that most likely it would be considered negligible. For example, one more subject taken into account could change, or even reverse the direction of the difference. Therefore, every good measure of relations between variables must take into account the overall differentiation of individual scores in the sample and evaluate the relation in terms of (relatively) how much of this differentiation is accounted for by the relation in question.
Common "General Format" of Most Statistical Tests
Common "General Format" of Most Statistical Tests
How the "Level of Statistical Significance" is Calculated
How the "Level of Statistical Significance" is Calculated
Thursday, October 27, 2011
Why the "Normal Distribution" is Important
Illustration of How the Normal Distribution is Used in Statistical Reasoning (Induction)
Are All Test Statistics Normally Distributed?
Are All Test Statistics Normally Distributed?
However, as the sample size (of samples used to create the sampling distribution of the mean) increases, the shape of the sampling distribution becomes normal. Note that for n=30, the shape of that distribution is "almost" perfectly normal (see the close match of the fit). This principle is called the central limit theorem (this term was first used by Pólya, 1920; German, "Zentraler Grenzwertsatz").
relationships between variables statistics
How Do We Know the Consequences of Violating the Normality Assumption?
Although many of the statements made in the preceding paragraphs can be proven mathematically, some of them do not have theoretical proof and can be demonstrated only empirically, via so-called Monte-Carlo experiments. In these experiments, large numbers of samples are generated by a computer following predesigned specifications, and the results from such samples are analyzed using a variety of tests. This way we can empirically evaluate the type and magnitude of errors or biases to which we are exposed when certain theoretical assumptions of the tests we are using are not met by our data. Specifically, Monte-Carlo studies were used extensively with normal distribution-based tests to determine how sensitive they are to violations of the assumption of normal distribution of the analyzed variables in the population. The general conclusion from these studies is that the consequences of such violations are less severe than previously thought. Although these conclusions should not entirely discourage anyone from being concerned about the normality assumption, they have increased the overall popularity of the distribution-dependent statistical tests in all areas of research.
Relational model
Reliability & Validity
We often think of reliability and validity as separate ideas but, in fact, they're related to each other. Here, I want to show you two ways you can think about their relationship.
How to be more Reliable in Your Relationships
How to be more Reliable in Your Relationships
reliable relationships
Reliable relationship
Speed of action, excellence in innovation and efficiency are important aspects of Nutrifeed’s business, as well as a dedication to meeting specific customer requirements.
Wednesday, October 26, 2011
mathematical relationships
Learning Breakthrough Interview: Brain Speed, Efficiency and Neural Networks
Relationship Quotes
Buddha
Spiritual relationship is far more precious than physical. Physical relationship divorced from spiritual is body without soul.
Mohandas Gandhi
If you haven't found it yet, keep looking. Don't settle. As with all matters of the heart, you'll know when you find it. And, like any great relationship, it just gets better and better as the years roll on.
Steve Jobs
When you make the sacrifice in marriage, you're sacrificing not to each other but to unity in a relationship.
Joseph Campbell
It is of practical value to learn to like yourself. Since you must spend so much time with yourself you might as well get so out of the relationship.
Norman Vincent Peale
There is no more lovely, friendly and charming relationship, communion or company than a good marriage.
Martin Luther
Sister is probably the most competitive relationship within the family, but once the sisters are grown, it becomes the strongest relationship.
Margaret Mead
A person isn't who they are during the last conversation you had with them - they're who they've been throughout your whole relationship.
Rainer Maria Rilke
So then, the relationship of self to other is the complete realization that loving yourself is impossible without loving everything defined as other than yourself.
Alan Watts
If the relationship of father to son could really be reduced to biology, the whole earth would blaze with the glory of fathers and sons.
James A. Baldwin
As soon as I got out there I felt a strange relationship with the pitcher's mound. It was as if I'd been born out there. Pitching just felt like the most natural thing in the world. Striking out batters was easy.
Babe Ruth
My relationship to power and authority is that I'm all for it. People need somebody to watch over them. Ninety-five percent of the people in the world need to be told what to do and how to behave.
Arnold Schwarzenegger
Whenever you're in conflict with someone, there is one factor that can make the difference between damaging your relationship and deepening it. That factor is attitude.
William James
If one could be friendly with women, what a pleasure - the relationship so secret and private compared with relations with men. Why not write about it truthfully?
Virginia Woolf
The first test of a truly great man is his humility. By humility I don't mean doubt of his powers or hesitation in speaking his opinion, but merely an understanding of the relationship of what he can say and what he can do.
John Ruskin
The relationship between a manufacturer and his advertising agency is almost as intimate as the relationship between a patient and his doctor. Make sure that you can life happily with your prospective client before you accept his account.
David Ogilvy
The relationship to one's fellow man is the relationship of prayer, the relationship to oneself is the relationship of striving; it is from prayer that one draws the strength for one's striving.
Franz Kafka
Never assume that the guy understands that you and he have a relationship.
Dave Barry
We have a strange and wonderful relationship - he's strange and I'm wonderful.
Mike Ditka
Courage means to keep working a relationship, to continue seeking solutions to difficult problems, and to stay focused during stressful periods.
Tuesday, October 25, 2011
Wednesday, October 12, 2011
Brother-in-Law, Sister-in-Law
These are the only really tricky in-law terms. “Brother-in-law” and “sister-in-law” each have two or three meanings. All authorities agree on the first two meanings, but there is some controversy about the third (and I personally don’t accept it).
My sister-in-law could be:
- the sister of my spouse, or
- the wife of my brother, or
- the wife of my spouse’s brother. (This meaning is accepted by The American Heritage Dictionary of the English Language (Third Edition, 1992), but not by all authorities.)
Similarly, my brother-in-law could be
- the brother of my spouse, or
- the husband of my sister, or
- the husband of my spouse’s sister. (This meaning is accepted by The American Heritage Dictionary of the English Language (Third Edition, 1992), but not by all authorities.)
Consider the following example: Al marries Betty; Betty has a sister Bonnie, who marries Calvin.
Harry = Sally | + -------------------- | | Al = Betty Bonnie = Calvin
The siblings-in-law:
- Al is Bonnie’s brother-in-law (definition 2), and Bonnie is Al’s sister-in-law (definition 1);
- Betty is Calvin’s sister-in-law (definition 1), and Calvin is Betty’s brother-in-law (definition 2).
So much is agreed. The question is, are Al and Calvin brothers-in-law (definition 3)? Someone once wrote to Ann Landers, the advice columnist, describing this situation. Ann replied: “You are no relation; you are just two men who married sisters.” Though I agree with Ann on this one, I admit that it’s awkward for Al to refer to Calvin as “my wife’s brother-in-law” or “my sister-in-law’s husband”. Probably that’s why Al might refer to Calvin as “my brother-in-law”.
Aunt, Uncle, Niece, Nephew
There are standard words for collateral relationships, where neither person is directly descended from the other. B0 and C0 are brother and sister, or more generically siblings. Going down one generation, on one side only, we have four common relationships:
- B0 is C1‘s uncle. Most English speakers use “uncle” for any of four relationships: father’s brother, mother’s brother, father’s sister’s husband, or mother’s sister’s husband.
- C0 is B1‘s aunt. Again, “aunt” in English could mean your father’s sister, mother’s sister, father’s brother’s wife, or mother’s brother’s wife. Most people would say Z0 is also C1‘s aunt.
- C1 is the niece or nephew of B0; most people would say C1 is also the niece or nephew of Z0.
Children of your aunt or uncle are your first cousins. More generally, B1 and C1, and all their descendants, are cousins to each other. A separate section below details all the words used to describe cousin relationships.