- Quality Improvement
- Talk To Minitab
What Statistical Hypothesis Test Should I Use?
Topics: Hypothesis Testing
So, you collected some data and now you want it to tell you something meaningful. Unfortunately, your last statistics class was years ago and you can't quite remember what to do with that data. You remember something about a null hypothesis and and alternative, but what's all this about testing?
Sometimes it's easier just to give a problem to the Assistant. Especially when it comes to statistics.
Don't get me wrong, I love to analyze data and see what it means...but most of us don't analyze data all day, every day. And in statistics, as in sports, if you don't use it, you lose it. If you haven't done an analysis in months it's not unreasonable to imagine you might need a little help.
In that case, you might seek out the Assistant. Specifically, the Assistant menu in Minitab Statistical Software . The Assistant's always ready to guide you through a difficult statistical task if you're not quite sure what to do.
The 2-Sample t-test
For example, suppose you want to compare two different materials for making backpacks –Cloth A and Cloth B –to determine which would make a more durable product. You sample materials from both suppliers and measure the mean amount of force needed to tear them.
If you're already up on your statistics, you know right away that you want to use a 2-sample t-test, which analyzes the difference between the means of your samples to determine whether that difference is statistically significant. You'll also know that the hypotheses of this two-tailed test would be:
- Null hypothesis: H0: m1 - m2 = 0 (strengths of the material from both companies are equal)
- Alternative hypothesis: H1: m1 - m2 ≠ 0 (strengths of the material from both companies are different)
And that if the test's p-value is less than your chosen significance level, you should reject the null hypothesis.
Maybe you're the type of person who remembers all of that stuff, even if you haven't done a t-test in years. If so, good for you–but I could stand to get a little help. Let's see what the assistant can do for me.
The Assistant and the Hypothesis Test
I'll start by pulling up Assistant > Hypothesis Tests... in Minitab. Up comes this dialog box:
Well, I know I have two samples that I want to compare. But I can't remember if I need a paired t-test, a % defective, or what. So I'll click "Help me choose." Now the Assistant gives me an easy-to-follow decision tree that leads me to the 2-sample t-test.
I can follow the tree straight to its conclusion, as shown on the right.
A Guided Path to the Right Hypothesis Test
But if I can't remember enough specifics to follow the decision tree from start to finish from the amount of information shown on the right, the Assistant will actually guide me through the process step-by-step so I arrive safely at the right hypothesis test to use.
In this scenario, The Assistant asks one question, then I choose the right option for my situation and proceed to the next question.
Particularly helpful is the fact that if I forget, for example, the difference between Continuous and Attribute data, all I have to do is click on a button and I'll get an explanation and an example for both.
In this situation, the questions I need to answer are:
- Do you have continuous data or attribute data? (Answer: Continuous)
- What are you comparing? (Answer: Two means)
- Are you measuring different sets of items or the same set of items? (Answer: Different sets)
Now I know what test I need to use to compare the two means. But I'm not sure I know how to do that test.
Fortunately, the Assistant can help me with that, too. I'll show you how in my next post .
Ready to try Minitab for yourself? Download a Free Trial today!
See how our experts can help your company better understand and utilize data. Learn more about our Training Services today!
You Might Also Like
- Trust Center
© 2023 Minitab, LLC. All Rights Reserved.
- Terms of Use
- Privacy Policy
- Cookies Settings
1-Sample Hypothesis Test
To add output from a 1-sample hypothesis test, go to Add and complete a form .
In This Topic
1 proportion, 1-sample wilcoxon, 1 variance test, 1-sample sign.
For example, you can test whether a new setting significantly changes the proportion defective. To see an example, go to Minitab Help: Example of 1 Proportion .
Data considerations
Your data must contain only two categories, such as pass/fail. For details, go to Minitab Help: Data considerations for 1 Proportion .
For example, you can test whether the mean output from the controlled improved process is different from the pre-project mean. To see an example, go to Minitab Help: Example of 1-Sample t .
The data must be continuous and reasonably normal. A 1-sample t-test is robust to violations of the normality assumption, especially if the sample size is large (n > 25). For more details, go to Minitab Help: Data considerations for 1-Sample t .
For example, you can test whether the mean output from the controlled improved process is different from the pre-project mean. To see an example, go to Minitab Help: Example of 1-Sample Wilcoxon .
Your data must be a continuous value for Y (output). The data should come from a symmetric distribution, such as the uniform or Cauchy distributions. If your data do not come from a symmetric distribution, use a 1-sample sign test. For more details, go to Minitab Help: Data considerations for 1-Sample Wilcoxon .
For example, a quality analyst uses a 1 variance test to determine whether the variance of the moisture content in a shipment of unprocessed lumber is too high. To see an example, go to Minitab Help: Example of 1 Variance .
Your data must be continuous Y (output) values. For more details, go to Minitab Help: Data considerations for 1 Variance .
For example, you can test whether the mean output from the controlled improved process is different from the pre-project mean. To see an example, go to Minitab Help: Example of 1-Sample Sign .
- Use the 1-sample t-test when the data are reasonably normal (or the sample size is large).
- Use the 1-sample Wilcoxon test as an alternative to the 1-sample t-test as long as the data are reasonably symmetric.
- Use the 1-sample sign test as a last resort.
- Minitab.com
- License Portal
- Cookie Settings
You are now leaving support.minitab.com.
Click Continue to proceed to:
IMAGES
VIDEO
COMMENTS
You can follow six basic steps to correctly set up and perform a hypothesis test. For example, the manager of a pipe manufacturing facility wants to determine whether the average diameter of their pipes is different from 5cm.
A hypothesis test is rule that specifies whether to accept or reject a claim about a population depending on the evidence provided by a sample of data. A hypothesis test examines two opposing hypotheses about a population: the null hypothesis and the alternative hypothesis.
What do significance levels and P values mean in hypothesis tests? What is statistical significance anyway? In this post, I’ll continue to focus on concepts and graphs to help you gain a more intuitive understanding of how hypothesis tests work in statistics.
To perform a hypothesis test, select Test median and enter a value. Use a hypothesis test to determine whether the population median (denoted as η) differs significantly from the hypothesized median (denoted as η 0 ) that you specify.
Hypothesis testing is an essential procedure in statistics. A hypothesis test evaluates two mutually exclusive statements about a population to determine which statement is best supported by the sample data. When we say that a finding is statistically significant, it’s thanks to a hypothesis test.
6b.2 - Minitab: One-Sample Mean Hypothesis Test. Minitab® – Conduct a One-Sample Mean t-Test. Note that these steps are very similar to those for one-mean confidence interval. The differences occur in steps 4 through 8. To conduct the one sample mean t-test in Minitab... Choose Stat > Basic Stat > 1 Sample t.
Learn how to choose which Statistical Hypothesis Test you should use using Minitab's Assistant Menu.
A hypothesis test for one proportion can be conducted in Minitab. This can be done using raw data or summarized data. If you have a data file with every individual's observation, then you have raw data.
The economist performs a 1-sample t-test to determine whether the monthly energy cost differs from $200. Open the sample data, FamilyEnergyCost.MTW. Choose Stat > Basic Statistics > 1-Sample t. From the drop-down list, select One or more samples, each in a column and enter. Select Perform hypothesis test, and in Hypothesized mean, enter 200.
Learn how to use 1-sample hypothesis tests to compare one sample with a hypothesized value in Minitab. Find out the data considerations, examples, and output for each test type: proportion, t, Wilcoxon, variance, and sign.