a hypothesis allows one to make ____ which can then be tested. course hero

What is hypothesis testing?

Hypothesis testing is a formal procedure for investigating our ideas about the world using statistics. It is most often used by scientists to test specific predictions, called hypotheses, that arise from theories. There are 5 main steps in hypothesis testing:

Where are the results of hypothesis testing presented?

The results of hypothesis testing will be presented in the results and discussion sections of your research paper.

Why is it important to restate a hypothesis?

After developing your initial research hypothesis (the prediction that you want to investigate), it is important to restate it as a null (H o) and alternate (H a) hypothesis so that you can test it mathematically. The alternate hypothesis is usually your initial hypothesis that predicts a relationship between variables.

How to test if there is a relationship between gender and height?

Based on your knowledge of human physiology, you formulate a hypothesis that men are, on average, taller than women. To test this hypothesis, you restate it as: H o: Men are, on average, not taller than women. H a: Men are, on average, taller than women.

What is the cutoff for rejecting a null hypothesis?

And in most cases, your cutoff for rejecting the null hypothesis will be 0.05 – that is, when there is a less than 5% chance that you would see these results if the null hypothesis were true.

What is the formal language of hypothesis testing?

In the formal language of hypothesis testing, we talk about rejecting or failing to reject the null hypothesis. You will probably be asked to do this in your statistics assignments.

What is the difference between null and alternate hypothesis?

The alternate hypothesis is usually your initial hypothesis that predicts a relationship between variables. The null hypothesis is a prediction of no relationship between the variables you are interested in. You want to test whether there is a relationship between gender and height.

What is hypothesis testing?

Hypothesis testing or significance testing is a method for testing a claim or hypothesis about a parameter in a population, using data measured in a sample. In this method, we test some hypothesis by determining the likelihood that a sample statistic could have been selected, if the hypothesis regarding the population parameter were true.

When we decide to retain the null hypothesis, we can be correct or incorrect.?

When we decide to retain the null hypothesis, we can be correct or incorrect. The correct decision is to retain a true null hypothesis. This decision is called a null result or null finding. This is usually an uninteresting decision because the decision is to retain what we already assumed: that the value stated in the null hypothesis is correct. For this reason, null results alone are rarely published in behavioral research.

What is the test statistic?

The test statistic is a mathematical formula that allows researchers to determine the likelihood of obtaining sample outcomes if the null hypothesis were true. The value of the test statistic is used to make a decision regarding the null hypothesis.

How does the alpha level affect the power of a test?

Increasing effect size, sample size, and the alpha level will increase power. The alpha level is the probability of a Type I error; it is the rejection region for a hypothesis test. The larger the rejection region, the greater the likelihood of rejecting the null hypothesis, and the greater the power will be. This is why one-tailed tests are more powerful than two- tailed tests: They increase alpha in the direction that an effect is expected to occur, thereby increasing the power to detect an effect.

Why is the likelihood of detecting an effect important?

The likelihood of detecting an effect, called power, is critical in behavioral research because it lets the researcher know the probability that a randomly selected sample will lead to a decision to reject the null hypothesis, if the null hypothesis is false. As effect size increases, power increases.

What is an alternative hypothesis?

An alternative hypothesis (H1) is a statement that directly contradicts a null hypothesis by stating that that the actual value of a population parameter is less than, greater than, or not equal to the value stated in the null hypothesis. Level of Significance.

Why do we test null hypothesis?

Remember that we are only testing the null hypothesis because we think it is wrong. Deciding to reject a false null hypothesis, then, is the power, inasmuch as we learn the most about populations when we accurately reject false notions of truth. This decision is the most published result in behavioral research.

What is hypothesis in science?

A hypothesis is an educated guess about how things work. It is an attempt to answer your question with an explanation that can be tested. A good hypothesis allows you to then make a prediction:

What happens if a scientist's prediction is not accurate?

Scientists often find that their predictions were not accurate and their hypothesis was not supported , and in such cases they will communicate the results of their experiment and then go back and construct a new hypothesis and prediction based on the information they learned during their experiment. This starts much of the process of the scientific method over again. Even if they find that their hypothesis was supported, they may want to test it again in a new way.

When do you start the scientific method?

The scientific method starts when you ask a question about something that you observe: How, What, When, Who, Which, Why, or Where.

How to complete a science fair project?

To complete your science fair project you will communicate your results to others in a final report and/or a display board. Professional scientists do almost exactly the same thing by publishing their final report in a scientific journal or by presenting their results on a poster or during a talk at a scientific meeting. In a science fair, judges are interested in your findings regardless of whether or not they support your original hypothesis.

Why can't a hypothesis be tested?

It doesn't matter whether or not you skip class. This hypothesis can't be tested because it doesn't make any actual claim regarding the outcome of skipping class. "It doesn't matter" doesn't have any specific meaning, so it can't be tested.

How to write a hypothesis?

Try to write the hypothesis as an if-then statement. If you take an action, then a certain outcome is expected. Identify the independent and dependent variable in the hypothesis. The independent variable is what you are controlling or changing. You measure the effect this has on the dependent variable.

What are the requirements for a testable hypothesis?

In order to be considered testable, two criteria must be met: It must be possible to prove that the hypothesis is true. It must be possible to prove that the hypothesis is false. It must be possible to reproduce the results of the hypothesis.

What is a testable hypothesis?

A hypothesis is a tentative answer to a scientific question. A testable hypothesis is a hypothesis that can be proved or disproved as a result of testing, data collection, or experience. Only testable hypotheses can be used to conceive and perform an experiment using the scientific method .

Is a hypothesis testable?

All the following hypotheses are testable. It's important, however, to note that while it's possible to say that the hypothesis is correct, much more research would be required to answer the question " why is this hypothesis correct?"

What is hypothesis testing?

Hypothesis testing is an act in statistics whereby an analyst tests an assumption regarding a population parameter. The methodology employed by the analyst depends on the nature of the data used and the reason for the analysis. Hypothesis testing is used to assess the plausibility of a hypothesis by using sample data.

What is the first step in a hypothesis analysis?

The first step is for the analyst to state the two hypotheses so that only one can be right.

How do statistical analysts test a hypothesis?

Statistical analysts test a hypothesis by measuring and examining a random sample of the population being analyzed. All analysts use a random population sample to test two different hypotheses: the null hypothesis and the alternative hypothesis.

What is the third step in a null hypothesis?

The third step is to carry out the plan and physically analyze the sample data. The fourth and final step is to analyze the results and either reject the null hypothesis, or state that the null hypothesis is plausible, given the data.

Is the alternative hypothesis true?

The alternative hypothesis is effectively the opposite of a null hypothesis ( e.g., the population mean return is not equal to zero). Thus, they are mutually exclusive, and only one can be true. However, one of the two hypotheses will always be true.

Is the null hypothesis true?

The null hypothesis is usually a hypothesis of equality between population parameters; e.g., a null hypothesis may state that the population mean return is equal to zero. The alternative hypothesis is effectively the opposite of a null hypothesis (e.g., the population mean return is not equal to zero). Thus, they are mutually exclusive , and only one can be true. However, one of the two hypotheses will always be true.

When forming a statistical hypothesis, the researcher examines the portion of a population of interest and makes a?

When forming a statistical hypothesis, the researcher examines the portion of a population of interest and makes a calculated assumption based on the data from this sample. A statistical hypothesis is most common with systematic investigations involving a large target audience. Here, it's impossible to collect responses from every member of the population so you have to depend on data from your sample and extrapolate the results to the wider population.

What is the purpose of a hypothesis in a research?

Typically, every research starts with a hypothesis—the investigator makes a claim and experiments to prove that this claim is true or false. For instance, if you predict that students who drink milk before class perform better than those who don't, then this becomes a hypothesis that can be confirmed or refuted using an experiment.

What are the Types of Hypotheses?

Also known as a basic hypothesis, a simple hypothesis suggests that an independent variable is responsible for a corresponding dependent variable. In other words, an occurrence of the independent variable inevitably leads to an occurrence of the dependent variable.

How to disapprove a null hypothesis?

To disapprove a null hypothesis, the researcher has to come up with an opposite assumption—this assumption is known as the alternative hypothesis. This means if the null hypothesis says that A is false, the alternative hypothesis assumes that A is true.

What is the purpose of a null hypothesis?

In this case, the purpose of the research is to approve or disapprove this assumption.

Why is hypothesis testing important?

The most significant benefit of hypothesis testing is it allows you to evaluate the strength of your claim or assumption before implementing it in your data set. Also, hypothesis testing is the only valid method to prove that something "is or is not". Other benefits include:

What is the purpose of research?

Research exists to validate or disprove assumptions about various phenomena. The process of validation involves testing and it is in this context that we will explore hypothesis testing.

What is hypothesis in science?

A hypothesis is an educated guess about how things work. It is an attempt to answer your question with an explanation that can be tested. A good hypothesis allows you to then make a prediction:#N#"If _____ [I do this] _____, then _____ [this] _____ will happen."

Why do scientists go back and construct a new hypothesis?

Scientists often find that their predictions were not accurate and their hypothesis was not supported , and in such cases they will communicate the results of their experiment and then go back and construct a new hypothesis and prediction based on the information they learned during their experiment.

What is the Scientific Method?

The scientific method is a process for experimentation that is used to explore observations and answer questions. Does this mean all scientists follow exactly this process? No. Some areas of science can be more easily tested than others. For example, scientists studying how stars change as they age or how dinosaurs digested their food cannot fast-forward a star's life by a million years or run medical exams on feeding dinosaurs to test their hypotheses. When direct experimentation is not possible, scientists modify the scientific method. In fact, there are probably as many versions of the scientific method as there are scientists! But even when modified, the goal remains the same: to discover cause and effect relationships by asking questions, carefully gathering and examining the evidence, and seeing if all the available information can be combined in to a logical answer.

What happens if an experiment is analyzed and a hypothesis is disproved?

If your hypothesis is disproved, then you can go back with the new information gained and create a new hypothesis to start the scientific process over again.

What happens if a scientist's prediction is not accurate?

Scientists often find that their predictions were not accurate and their hypothesis was not supported , and in such cases they will communicate the results of their experiment and then go back and construct a new hypothesis and prediction based on the information they learned during their experiment. This starts much of the process of the scientific method over again. Even if they find that their hypothesis was supported, they may want to test it again in a new way.

How to find evidence for an answer?

If you want to find evidence for an answer or an answer itself then you construct a hypothesis and test that hypothesis in an experiment. If the experiment works and the data is analyzed you can either prove or disprove your hypothesis.

How do scientists use the scientific method?

But scientists always strive to keep to the core principles of the scientific method by using observations, experiments, and data to support or reject explanations of how a phenomenon works. While experimenting is considered the best way to test explanations, there are areas of science, like astronomy, where this is not always possible.