I’m stuck on how to value the null or alternative hypotheses

: In everyday language, the word usually refers to an educated guess — or an idea that we are quite uncertain about. Scientific hypotheses, however, are much more informed than any guess and are usually based on prior experience, scientific background knowledge, preliminary observations, and logic. In addition, hypotheses are often supported by many different lines of evidence — in which case, scientists are more confident in them than they would be in any mere "guess." To further complicate matters, science textbooks frequently misuse the term in a slightly different way. They may ask students to make a about the outcome of an experiment (e.g., table salt will dissolve in water more quickly than rock salt will). This is simply a prediction or a guess (even if a well-informed one) about the outcome of an experiment. Scientific hypotheses, on the other hand, have explanatory power — they are explanations for phenomena. The idea that table salt dissolves faster than rock salt is not very hypothesis-like because it is not very explanatory. A more scientific (i.e., more explanatory) hypothesis might be "The amount of surface area a substance has affects how quickly it can dissolve. More surface area means a faster rate of dissolution." This hypothesis has some explanatory power — it gives us an idea of a particular phenomenon occurs — and it is testable because it generates expectations about what we should observe in different situations. If the hypothesis is accurate, then we'd expect that, for example, sugar processed to a powder should dissolve more quickly than granular sugar. Students could examine rates of dissolution of many different substances in powdered, granular, and pellet form to further test the idea. The statement "Table salt will dissolve in water more quickly than rock salt" is not a hypothesis, but an expectation generated by a hypothesis. Textbooks and science labs can lead to confusions about the difference between a hypothesis and an expectation regarding the outcome of a scientific test. To learn more about scientific hypotheses, visit in our section on how science works.

With the information we gather from our senses, we can make inferences using our reason and logic.

State the null hypothesis. In this case, the null hypothesis is that the population mean is 18.9, so we write:
H0: μ = 18.9


Feb 24, 2014 · Can you figure out the rule

Scientists cannot usually check every possible situation where a hypothesis might apply.

When we are dealing with one of a kind events that are very complex, for example the drop in U.S. crime rates in the 1990's, there may be so many interacting factors to consider that a definitive answer becomes impossible. It is entirely possible that radically different, possibly even mutually exclusive hypotheses, may be equally supported by data. It is also entirely possible that hypothesis successfully explains all the data, or that every hypothesis is contradicted by some data. But in a world full of interacting forces, occasional contradictions don't disprove an idea. The fact that lightning hits a valley and misses a hilltop doesn't disprove the idea that lightning tends to hit high points. It merely proves it doesn't hit high points.


Of course you can't disprove the Omphalos hypothesis

Alternative hypothesis – SCL will have a significance effect on how primary school students learn English skills compared to when they’re taught using a teacher-centered approach

Steps in Proving a Hypothesis | Synonym

Null hypothesis- SCL approach will have no effect on how primary school students learn English skills compared to when they’re taught using a teacher-centered approach

Reaffirm or disprove my hypothesis

But one scientist desperately wants to believe there's out there because it's comforting to think there might be a guardian preventing us from destroying ourselves. And the other one just as desperately wants not to believe because he's still rebelling against his strict parents after all these years. So we can have perfectly sound rival interpretations of the evidence, but reasons for picking one interpretation over the other. Just as with the crime question, people can be right for the wrong reasons.

24.02.2014 · Can you figure out the rule

CORRECTION: When scientists are portrayed in movies and television shows, they are often ensconced in silent laboratories, alone with their bubbling test-tubes. This can make science seem isolating. In fact, many scientists work in busy labs or field stations, surrounded by other scientists and students. Scientists often collaborate on studies with one another, mentor less experienced scientists, and just chat about their work over coffee. Even the rare scientist who works entirely alone depends on interactions with the rest of the scientific community to scrutinize his or her work and get ideas for new studies. Science is a social endeavor. To learn more, visit our section on the .