Independent variables are isolated from other factors of the study. Dependent variables , as name suggests are dependent on other factors of the study. They are influenced by the change in independent variable. Example 1 The greater number of coal plants in a region independent variable increases water pollution dependent variable.
If you change the independent variable building more coal factories , it will change the dependent variable amount of water pollution. Example 2 What is the effect of diet or regular soda independent variable on blood sugar levels dependent variable? If you change the independent variable the type of soda you consume , it will change the dependent variable blood sugar levels.
You should not ignore the importance of the above steps. The validity of your experiment and its results rely on a robust testable hypothesis. Developing a strong testable hypothesis has few advantages, it compels us to think intensely and specifically about the outcomes of a study.
Consequently, it enables us to understand the implication of the question and the different variables involved in the study. Furthermore, it helps us to make precise predictions based on prior research.
Hence, forming a hypothesis would be of great value to the research. Here are some good examples of testable hypotheses. More importantly, you need to build a robust testable research hypothesis for your scientific experiments. A testable hypothesis is a hypothesis that can be proved or disproved as a result of experimentation. To devise and perform an experiment using scientific method, you need to make sure that your hypothesis is testable.
To be considered testable, some essential criteria must be met:. Without these criteria, the hypothesis and the results will be vague. If a first-year student starts attending more lectures , then their exam scores will improve.
In academic research, hypotheses are more commonly phrased in terms of correlations or effects, where you directly state the predicted relationship between variables. The number of lectures attended by first-year students has a positive effect on their exam scores.
If you are comparing two groups, the hypothesis can state what difference you expect to find between them. First-year students who attended most lectures will have better exam scores than those who attended few lectures. If your research involves statistical hypothesis testing , you will also have to write a null hypothesis. The null hypothesis is the default position that there is no association between the variables. The null hypothesis is written as H 0 , while the alternative hypothesis is H 1 or H a.
H 0 : The number of lectures attended by first-year students has no effect on their final exam scores. H 1 : The number of lectures attended by first-year students has a positive effect on their final exam scores.
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Do the check. Generate your APA citations for free! APA Citation Generator. Home Knowledge Base Methodology How to write a hypothesis. What can proofreading do for your paper? Is this article helpful? Its value is set before the hypothesis test starts. The p -value is calculated from the data. You are testing that the mean speed of your cable Internet connection is more than three Megabits per second. What is the random variable? Describe in words.
The American family has an average of two children. The mean entry level salary of an employee at a company is? You believe it is higher for IT professionals in the company. A sociologist claims the probability that a person picked at random in Times Square in New York City is visiting the area is 0. You want to test to see if the proportion is actually less.
The random variable is the proportion of people picked at random in Times Square visiting the city. You want to test to see if the claim is correct.
A test is conducted to see if, in fact, the proportion is less. Suppose that a recent article stated that the mean time spent in jail by a first—time convicted burglar is 2. A study was then done to see if the mean time has increased in the new century. A random sample of 26 first-time convicted burglars in a recent year was picked. The mean length of time in jail from the survey was 3 years with a standard deviation of 1.
Suppose that it is somehow known that the population standard deviation is 1. If you were conducting a hypothesis test to determine if the mean length of jail time has increased, what would the null and alternative hypotheses be?
The distribution of the population is normal. A random survey of 75 death row inmates revealed that the mean length of time on death row is If you were conducting a hypothesis test to determine if the population mean time on death row could likely be 15 years, what would the null and alternative hypotheses be? The National Institute of Mental Health published an article stating that in any one-year period, approximately 9.
Suppose that in a survey of people in a certain town, seven of them suffered from depression or a depressive illness. If you were conducting a hypothesis test to determine if the true proportion of people in that town suffering from depression or a depressive illness is lower than the percent in the general adult American population, what would the null and alternative hypotheses be? Some of the following statements refer to the null hypothesis, some to the alternate hypothesis.
State the null hypothesis, H 0 , and the alternative hypothesis. Researchers surveyed a group of randomly selected teen girls living in Massachusetts between 12 and 15 years old. After four years the girls were surveyed again. Sixty-three said they smoked to stay thin. Is there good evidence that more than thirty percent of the teen girls smoke to stay thin?
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