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Three types of hypotheses

Hypothesis

* Simple hypothesis

* Complex hypothesis

* Null hypothesis

What is a hypothesis

A hypothesis states your predictions about what your research will find. It is a tentative answer to your research question that has not yet been tested. For some research projects, you might have to write several hypotheses that address different aspects of your research question.

A hypothesis is not just a guess — it should be based on existing theories and knowledge. It also has to be testable, which means you can support or refute it through scientific research methods (such as experiments, observations and statistical analysis of data).

Variables in hypotheses

Hypotheses propose a relationship between two or more variables. An independent variable is something the researcher changes or controls. A dependent variable is something the researcher observes and measures.

Daily apple consumption leads to fewer doctor’s visits.

In this example, the independent variable is apple consumption — the assumed cause. The dependent variable is the frequency of doctor’s visits — the assumed effect.

Three steps to hypothesis testing

  • State the null hypothesis and alternative hypothesis
  • Decide on test static and critical value
  • Compute p-value. If P-value is less than the critical value reject the null hypothesis and accept the alternative hypothesis

Simple hypothesis

Simple hypotheses are ones which give probabilities to potential observations. The contrast here is with complex hypotheses, also known as models, which are sets of simple hypotheses such that knowing that some member of the set is true (but not which) is insufficient to specify probabilities of data points.

Normal curve​
Simple hypothesis – Bell Curve

Complex hypothesis

Complex hypothesis is that one in which there are multiple dependent as well as independent variables. Example: Global warming causes icebergs to melt which in turn causes major changes in weather patterns.

Complex hypothesis
Complex hypothesis

Null hypothesis

A null hypothesis is a hypothesis that says there is no statistical significance between the two variables in the hypothesis. … For example, a null hypothesis would be something like this: There is no statistically significant relationship between the type of water I feed the flowers and growth of the flowers.

null hypothesis
Null hypothesis

Create a Null Hypothesis

Depending on your study, you may need to perform some statistical analysis on the data you collect. When forming your hypothesis statement using the scientific method, it’s important to know the difference between a null hypothesis vs. the alternative hypothesis, and how to create a null hypothesis. 

  • A null hypothesis, often denoted as H0, posits that there is no apparent difference or that there is no evidence to support a difference. Using the motivation example above, the null hypothesis would be that sleep hours have no effect on motivation.
  • An alternative hypothesis, often denoted as H1, states that there is a statistically significant difference, or there is evidence to support such a difference. Going back to the same carrot example, the alternative hypothesis is that a person getting six hours of sleep has less motivation than someone getting eight hours of sleep.
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Cantor’s threefold division of infinity

Excerpts from Infinity and the Mind

Rudy Rucker
Infinity and the mind by Rudy Rucker
Infinity and the Mind

… This threefold division [of infinity] is due to Cantor, who, in the following passage, distinguishes between the:

  • Absolute Infinite
  • Physical infinities
  • Mathematical infinities

The actual infinite arises in three contexts: first when it is realized in the most complete form, in a fully indepen dent other-worldly being, in Deo, where I call it the Absolute Infinite or simply Absolute; second when it occurs in the contingent, created world; third when the mind grasps it in abstracto as a mathematical magnitude, number, or order type. I wish to make a sharp contrast between the Absolute and what I call the Transfinite, that is, the actual infinities of the last two sorts, which are clearly limited, subject to further increase, and thus related to the finite,

PHYSICAL INFINITIES

There are three ways in which our world appears to be un bounded and thus, perhaps, infinite. It seems that time cannot end. It seems that space cannot end. And it seems that any interval of space or time can be divided and subdivided endlessly. We will consider these three apparent physical infinities in three subsections.

Temporal Infinities

One of the chief consequences of Einstein’s Special Theory of Relativity is that it is space-time that is fundamental, not isolated space which evolves as time passes. I will not argue this point in detail here, but let me repeat that on the basis of modern physical theory we have every reason to think of the passage of time as an illusion. Past, present, and future all exist together in space-time.

So the question of the infinitude of time is not one that is to be dodged by denying that time can be treated as a fixed dimension such as space. The question still remains: is time infinite? If we take the entire space-time of our universe, is the time dimension infinitely extended or not?

Möbius strip ​
Möbius strip

Spatial Infinities

Whether or not our space is actually infinite is a question that could conceivably be resolved in the next few decades. Assuming that Einstein’s theory of gravitation is correct, there are basically two types of universe: i) a hyperspherical (closed and
unbounded) space that expands, and then contracts back to a point; ii) an infinite space that expands forever. It is my guess that case i) will come to be most widely accepted, if only because the notion of an actually infinite space extending out in every direction is so unsettling.

The fate of the universe in case i) is certainly more interesting, since such a universe collapses back to an infinitely dense space-time singularity that may serve as the seed for a whole new universe. In case il), on the other hand, we simply have cooling and dying suns drifting further and further apart in an utterly empty black immensity … and in the end there are only ashes and cinders in an absolute and eternal night.

The question we are concerned with here is whether or not space is infinitely large. There seem to be three options: i) There is some level n for which -dimensional space is real and infinitely extended. The situation where our three-dimensional space is infinitely large falls under this case. ii). There is some n such that there is only one n-dimensional space. This space is to be finite and unbounded, and there is to be no reality to n + 1 dimensional space.

The situation where our three-dimensional space is finite and unbounded, and the reality of four-dimensional space denied, falls under this case. iii). There are real spaces of every dimension, and each of these spaces is finite and unbounded. In this case we either have an infinite number of universes, duoverses, triverses, etc., or we reach a level after which there is only one n-verse for each n.

Read more in his book Infinity and the Mind

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Three geometries – Euclidean, Hyperbolic, Elliptical

Three geometries - Euclidean, Hyperbolic, Elliptical
Three geometries – Euclidean, Hyperbolic, Elliptical

There are precisely three different classes of three-dimensional constant-curvature geometry: Euclidean, hyperbolic and elliptic geometry. The three geometries are all built on the same first four axioms, but each has a unique version of the fifth axiom, also known as the parallel postulate. The 1868 Essay on an Interpretation of Non-Euclidean Geometry by Eugenio Beltrami (1835 – 1900) proved the logical consistency of the two Non-Euclidean geometries, hyperbolic and elliptical.

The parallel postulate is as follows for the corresponding geometries.

Euclidean geometry: Playfair’s version: “Given a line l and a point P not on l, there exists a unique line m through P that is parallel to l.” Euclid’s version: “Suppose that a line l meets two other lines m and nso that the sum of the interior angles on one side of lis less than 180°. Then m and n intersect in a point on that side of l.” These two versions are equivalent; though Playfair’s may be easier to conceive, Euclid’s is often useful for proofs.

Hyperbolic geometry: Given an arbitrary infinite line l and any point P not on l, there exist two or more distinct lines which pass through P and are parallel to l.

Elliptic geometry: Given an arbitrary infinite line land any point P not on l, there does not exist a line which passes through P and is parallel to l.

Source and more info: https://en.m.wikibooks.org/wiki/Geometry/Hyperbolic_and_Elliptic_Geometry