ThoughtCo / Hilary Allison Updated on September 04, 2019 The null hypothesis—which assumes that there is no meaningful relationship between two variables—may be the most
valuable hypothesis for the scientific method because it is the easiest to test using a statistical analysis. This means you can support your hypothesis with a high level of confidence. Testing the null hypothesis can tell you whether your results are due to the effect of manipulating
the dependent variable or due to chance. The null hypothesis states there is no relationship between the measured phenomenon (the dependent variable) and
the independent variable. You do not need to believe that the null hypothesis is true to test it. On the contrary, you will likely suspect that there is a relationship between a set of variables. One way to prove that this is the case is to reject the null hypothesis. Rejecting a hypothesis does not mean an
experiment was "bad" or that it didn't produce results. In fact, it is often one of the first steps toward further inquiry. To distinguish it from other hypotheses, the null hypothesis is written as H0 (which is read as “H-nought,” "H-null," or "H-zero"). A significance test is used to determine the likelihood that the results supporting the null hypothesis are not due to chance. A confidence level of 95 percent or 99 percent is
common. Keep in mind, even if the confidence level is high, there is still a small chance the null hypothesis is not true, perhaps because the experimenter did not account for a critical factor or because of chance. This is one reason why it's important to repeat experiments. To write a null hypothesis, first start by asking a question. Rephrase that question in a form that assumes
no relationship between the variables. In other words, assume a treatment has no effect. Write your hypothesis in a way that reflects this.
Learning Outcomes
The actual test begins by considering two hypotheses. They are called the null hypothesis and the alternative hypothesis. These hypotheses contain opposing viewpoints. H0: The null hypothesis: It is a statement about the population that either is believed to be true or is used to put forth an argument unless it can be shown to be incorrect beyond a reasonable doubt. Ha: The alternative hypothesis: It is a claim about the population that is contradictory to H0 and what we conclude when we reject H0. Since the null and alternative hypotheses are contradictory, you must examine evidence to decide if you have enough evidence to reject the null hypothesis or not. The evidence is in the form of sample data. After you have determined which hypothesis the sample supports, you make adecision. There are two options for a decision. They are “reject H0” if the sample information favors the alternative hypothesis or “do not reject H0” or “decline to reject H0” if the sample information is insufficient to reject the null hypothesis. Mathematical Symbols Used in H0 and Ha:
NoteH0 always has a symbol with an equal in it. Ha never has a symbol with an equal in it. The choice of symbol depends on the wording of the hypothesis test. However, be aware that many researchers (including one of the co-authors in research work) use = in the null hypothesis, even with > or < as the symbol in the alternative hypothesis. This practice is acceptable because we only make the decision to reject or not reject the null hypothesis. ExampleH0: No more than 30% of the registered voters in Santa Clara County voted in the primary election. p ≤ 30 Ha: More than 30% of the registered voters in Santa Clara County voted in the primary election. p > 30 try itA medical trial is conducted to test whether or not a new medicine reduces cholesterol by 25%. State the null and alternative hypotheses. H0 : The drug reduces cholesterol by 25%. p = 0.25 Ha : The drug does not reduce cholesterol by 25%. p ≠ 0.25 ExampleWe want to test whether the mean GPA of students in American colleges is different from 2.0 (out of 4.0). The null and alternative hypotheses are: H0: μ = 2.0 Ha: μ ≠ 2.0 try itWe want to test whether the mean height of eighth graders is 66 inches. State the null and alternative hypotheses. Fill in the correct symbol (=, ≠, ≥, <, ≤, >) for the null and alternative hypotheses. H0: μ __ 66 Ha:μ __ 66
ExampleWe want to test if college students take less than five years to graduate from college, on the average. The null and alternative hypotheses are: H0: μ ≥ 5 Ha: μ < 5 try itWe want to test if it takes fewer than 45 minutes to teach a lesson plan. State the null and alternative hypotheses. Fill in the correct symbol ( =, ≠, ≥, <, ≤, >) for the null and alternative
hypotheses.
ExampleIn an issue of U.S. News and World Report, an article on school standards stated that about half of all students in France, Germany, and Israel take advanced placement exams and a third pass. The same article stated that 6.6% of U.S. students take advanced placement exams and 4.4% pass. Test if the percentage of U.S. students who take advanced placement exams is more than 6.6%. State the null and alternative hypotheses. H0: p ≤ 0.066 Ha: p > 0.066 try itOn a state driver’s test, about 40% pass the test on
the first try. We want to test if more than 40% pass on the first try. Fill in the correct symbol (=, ≠, ≥, <, ≤, >) for the null and alternative hypotheses.
Concept ReviewIn a hypothesis test, sample data is evaluated in order to arrive at a decision about some type of claim. If certain conditions about the sample are satisfied, then the claim can be evaluated for a population. In a hypothesis test, we: Evaluate the null hypothesis, typically denoted with H0. The null is not rejected unless the hypothesis test shows otherwise. The null statement must always contain some form of equality (=, ≤ or ≥) Always write the alternative hypothesis, typically denoted with Ha or H1, using less than, greater than, or not equals symbols, i.e., (≠, >, or <). If we reject the null hypothesis, then we can assume there is enough evidence to support the alternative hypothesis. Never state that a claim is proven true or false. Keep in mind the underlying fact that hypothesis testing is based on probability laws; therefore, we can talk only in terms of non-absolute certainties. Formula ReviewH0 and Ha are contradictory. How do you write a null and alternative hypothesis?When the research question asks “Does the independent variable affect the dependent variable?”:. The null hypothesis (H0) answers “No, there's no effect in the population.”. The alternative hypothesis (Ha) answers “Yes, there is an effect in the population.”. How do you write a null hypothesis for a research paper?To write a null hypothesis, first start by asking a question. Rephrase that question in a form that assumes no relationship between the variables. In other words, assume a treatment has no effect. Write your hypothesis in a way that reflects this.
|
How to write null and alternative hypothesis in research paper
Related Posts
Copyright © 2024 membukakan Inc.
