what does it mean if your test result is "statistically significant"? course hero

by Dr. Geoffrey Moen 5 min read

If a result is statistically significant, that means it’s unlikely to be explained solely by chance or random factors. In other words, a statistically significant result has a very low chance of occurring if there were no true effect in a research study.

Full Answer

What is a statistically significant result?

A statistically significant result would be one where, after rigorous testing, you reach a certain degree of confidence in the results. We call that degree of confidence our confidence level, which demonstrates how sure we are that our data was not skewed by random chance.

What is the significance level for a 5% Test?

Usually, the significance level is set to 0.05 or 5%. That means your results must have a 5% or lower chance of occurring under the null hypothesis to be considered statistically significant. The significance level can be lowered for a more conservative test. That means an effect has to be larger to be considered statistically significant.

How do you test for statistical significance in research?

How do you test for statistical significance? In quantitative research, data are analyzed through null hypothesis significance testing, or hypothesis testing. This is a formal procedure for assessing whether a relationship between variables or a difference between groups is statistically significant.

How can statistical significance be misunderstood?

Statistical significance can be misinterpreted when researchers do not use language carefully in reporting their results. Statistical significance does not always indicate practical significance, meaning the results cannot be applied to real-world business situations.

How do you test for statistical significance?

When reporting statistical significance, do you include descriptive statistics?

Why is the significance level higher?

What does the p value tell you about a statistically significant finding?

How are P-values calculated?

Why is statistical significance misleading?

What is the difference between null hypothesis and alternative hypothesis?

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What does it mean if your test result is statistically significant?

A result of an experiment is said to have statistical significance, or be statistically significant, if it is likely not caused by chance for a given statistical significance level. Your statistical significance level reflects your risk tolerance and confidence level.

What does it mean if a result is statistically significant quizlet?

Statistical significance means that the result observed in a sample is unusual when the null hypothesis is assumed to be true. When testing a hypothesis using the​ P-value Approach, if the​ P-value is​ large, reject the null hypothesis.

What does it mean to say that the results of a study are not statistically significant?

This means that the results are considered to be „statistically non-significant‟ if the analysis shows that differences as large as (or larger than) the observed difference would be expected to occur by chance more than one out of twenty times (p > 0.05).

What does it mean to say that the results of a study are not statistically significant quizlet?

If the result is not statistically significant and the sample size is small, the result is inconclusive. • If the result is not statistically significant and the sample size is large, the research hypothesis is likely false. Effect Size and Power in Research Articles.

What does a .05 level of significance mean quizlet?

a .05 level of significance means that: there is only a 5 percent chance that a statistic's value could be obtained as a result of random error.

When a difference between two groups is statistically significant This means that quizlet?

When a difference between two groups is statistically significant, this means that... the difference is not likely to have occurred on its own, without the benefit of the independent variable. A sample average can be used to estimate a population average with greater precision if the sample is... large.

What does statistical significance mean in psychology?

the degree to which a research outcome cannot reasonably be attributed to the operation of chance or random factors.

What is the difference between statistical significance and practical significance quizlet?

Statistical significance means that the hypothesis test being performed is useful for building theoretical foundations for other statistical work. Practical significance means that the particular application of the hypothesis test is of great importance to the real world.

Statistical Significance Calculator

This statistical significance calculator can help you determine the value of the comparative error, difference & the significance for any given sample size and percentage response.

How To Calculate Statistical Significance (And Its Importance)

If you're trying to determine the effectiveness of something, consider calculating statistical significance. Though it's known for being taught in statistics coursework, it can be used for a variety of different industries including business.

What Is Statistical Significance? How Is It Calculated? - PrepScholar

Melissa Brinks graduated from the University of Washington in 2014 with a Bachelor's in English with a creative writing emphasis. She has spent several years tutoring K-12 students in many subjects, including in SAT prep, to help them prepare for their college education.

Statistical Significance Definition: Types and How It's Calculated

Statistical significance means that a result from testing or experimenting is not likely to occur randomly or by chance, but is instead likely to be attributable to a specific cause. Statistical ...

How do you test for statistical significance?

This is a formal procedure for assessing whether a relationship between variables or a difference between groups is statistically significant .

When reporting statistical significance, do you include descriptive statistics?

When reporting statistical significance, include relevant descriptive statistics about your data (e.g. means and standard deviations) as well as the test statistic and p value.

Why is the significance level higher?

This makes the study less rigorous and increases the probability of finding a statistically significant result.

What does the p value tell you about a statistically significant finding?

In other words, a statistically significant result has a very low chance of occurring if there were no true effect in a research study . The p value, or probability value, tells you the statistical significance of a finding.

How are P-values calculated?

P -values are calculated from the null distribution of the test statistic. They tell you how often a test statistic is expected to occur under the null hypothesis of the statistical test, based on where it falls in the null distribution.

Why is statistical significance misleading?

On its own, statistical significance may also be misleading because it’s affected by sample size. In extremely large samples, you’re more likely to obtain statistically significant results, even if the effect is actually small or negligible in the real world. This means that small effects are often exaggerated if they meet the significance threshold, while interesting results are ignored when they fall short of meeting the threshold.

What is the difference between null hypothesis and alternative hypothesis?

A null hypothesis (H 0) always predicts no true effect, no relationship between variables, or no difference between groups. An alternative hypothesis ( H a or H 1) states your main prediction of a true effect, a relationship between variables, or a difference between groups. Hypothesis testing always starts with the assumption ...

What is the level at which one can accept whether an event is statistically significant?

The level at which one can accept whether an event is statistically significant is known as the significance level. Researchers use a test statistic known as the p-value to determine statistical significance: if the p-value falls below the significance level, then the result is statistically significant. The p-value is a function of the means and ...

What Is Statistical Significance?

Statistical significance refers to the claim that a result from data generated by testing or experimentation is not likely to occur randomly or by chance but is instead likely to be attributable to a specific cause. Having statistical significance is important for academic disciplines or practitioners that rely heavily on analyzing data and research, such as economics, finance, investing, medicine, physics, and biology.

What does p-value mean in statistics?

The p-value indicates the probability under which the given statistical result occurred, assuming chance alone is responsible for the result. If this probability is small, then the researcher can safely rule our chance as a cause. The p-value must fall under the significance level for the results to at least be considered statistically significant.

What is null hypothesis?

The Null Hypothesis. All these factors have what is called null hypotheses, and significance often is the goal of hypothesis testing in statistics. The most common null hypothesis is that the parameter in question is equal to zero (typically indicating that a variable has zero effect on the outcome of interest).

Why is sample size important in statistical analysis?

Sample size is an important component of statistical significance in that larger samples are less prone to flukes. Only random, representative samples should be used in significance testing. The level at which one can accept whether an event is statistically significant is known as the significance level.

What is the confidence level for a null hypothesis?

If you can reject the null hypothesis with a confidence of 95 percent or better, researchers can invoke statistical significance. Null hypotheses can also be tested for the equality (rather than equal to zero) of effect for two or more alternative treatments—for example, between a drug and a placebo in a clinical trial.

What is the opposite of the significance level?

The opposite of the significance level, calculated as 1 minus the significance level, is the confidence level . It indicates the degree of confidence that the statistical result did not occur by chance or by sampling error. The customary confidence level in many statistical tests is 95%, leading to a customary significance level or p-value of 5%.

What does it mean when a test is statistically significant?

If you run an experiment and your p-valu e is less than your alpha (significance) level, your test is statistically significant. If your confidence interval doesn't contain your null hypothesis value, your test is statistically significant.

What Is Statistical Significance? How Is It Calculated?

If you've ever read a wild headline like, "Study Shows Chewing Rocks Prevents Cancer," you've probably wondered how that could be possible. If you look closer at this type of article you may find that the sample size for the study was a mere handful of people. If one person in a group of five chewed rocks and didn't get cancer, does that mean chewing rocks prevented cancer?

What is the significance level of a null hypothesis?

Third, you'll want to set the significance level, also known as alpha, or α. The alpha is the probability of rejecting a null hypothesis when that hypothesis is true. In the case of our fertilizer example, the alpha is the probability of concluding that the fertilizer does make plants treated with it grow more when the fertilizer does not actually have an effect.

What is the opposite of a null hypothesis?

Next, you need an alternative hypothesis , H a. Your alternative hypothesis is generally the opposite of your null hypothesis, so in this case it would be something like, "This fertilizer will cause the plants who get treated with it to grow faster."

Why do we use calculators?

Calculators make calculating statistical significance a lot easier. Most people will do their calculations this way instead of by hand, as doing them without tools is more likely to introduce errors in an already sensitive process. To get you started, here are some calculators you can use to make your work simpler:

What is the difference between a one-tailed and a two-tailed test?

Fourth, you'll need to decide whether a one- or two-tailed test is more appropriate. One-tailed tests examine the relationship between two things in one direction, such as if the fertilizer makes the plant grow. A two-tailed test measures in two directions, such as if the fertilizer makes the plant grow or shrink.

Why is the conclusion reached in it not valid?

What that means is that the conclusion reached in it isn't valid, because there's not enough evidence that what happened was not random chance. A statistically significant result would be one where, after rigorous testing, you reach a certain degree of confidence in the results.

What does it mean to be statistically significant?

In short, “statistically significant” means that there is a low probability that a result as great or greater than the observed result could arise if there is actually no effect of the thing being tested.

What is a 95% confidence interval?

Note: An important topic not covered here is confidence intervals. These show you the range of possible population values for a given sample value. So, for example, if you had a mean of 20 and a 95% confidence interval of 10-30, that would mean that you can be 95% sure that the population mean is between 10 and 30.

How do you test for statistical significance?

This is a formal procedure for assessing whether a relationship between variables or a difference between groups is statistically significant .

When reporting statistical significance, do you include descriptive statistics?

When reporting statistical significance, include relevant descriptive statistics about your data (e.g. means and standard deviations) as well as the test statistic and p value.

Why is the significance level higher?

This makes the study less rigorous and increases the probability of finding a statistically significant result.

What does the p value tell you about a statistically significant finding?

In other words, a statistically significant result has a very low chance of occurring if there were no true effect in a research study . The p value, or probability value, tells you the statistical significance of a finding.

How are P-values calculated?

P -values are calculated from the null distribution of the test statistic. They tell you how often a test statistic is expected to occur under the null hypothesis of the statistical test, based on where it falls in the null distribution.

Why is statistical significance misleading?

On its own, statistical significance may also be misleading because it’s affected by sample size. In extremely large samples, you’re more likely to obtain statistically significant results, even if the effect is actually small or negligible in the real world. This means that small effects are often exaggerated if they meet the significance threshold, while interesting results are ignored when they fall short of meeting the threshold.

What is the difference between null hypothesis and alternative hypothesis?

A null hypothesis (H 0) always predicts no true effect, no relationship between variables, or no difference between groups. An alternative hypothesis ( H a or H 1) states your main prediction of a true effect, a relationship between variables, or a difference between groups. Hypothesis testing always starts with the assumption ...

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How Do You Test For Statistical significance?

  • In quantitative research, data are analyzed through null hypothesis significance testing, or hypothesis testing. This is a formal procedure for assessing whether a relationship between variables or a difference between groups is statistically significant.
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What Is A Significance level?

  • The significance level, or alpha (α), is a value that the researcher sets in advance as the threshold for statistical significance. It is the maximum risk of making a false positive conclusion (Type I error) that you are willing to accept. In a hypothesis test, the pvalue is compared to the significance level to decide whether to reject the null hypothesis. 1. If thep value is higher than t…
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Problems with Relying on Statistical Significance

  • There are various critiques of the concept of statistical significance and how it is used in research. Researchers classify results as statistically significant or non-significant using a conventional threshold that lacks any theoretical or practical basis. This means that even a tiny 0.001 decrease in a pvalue can convert a research finding from s...
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Other Types of Significance in Research

  • Aside from statistical significance, clinical significance and practical significance are also important research outcomes. Practical significance shows you whether the research outcome is important enough to be meaningful in the real world. It’s indicated by the effect sizeof the study. Clinical significanceis relevant for intervention and treatment studies. A treatment is considered …
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