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What should be the P value for normality test?
The test rejects the hypothesis of normality when the p-value is less than or equal to 0.05. Failing the normality test allows you to state with 95% confidence the data does not fit the normal distribution. Passing the normality test only allows you to state no significant departure from normality was found.
How do you do normal distribution on Minitab?
Minitab can calculate probabilities from many different distributions. These calculations are called from the Calc menu. Specifically, for the normal distribution, Calc → Probability Distributions → Normal …
What should a normal probability plot look like?
A normal probability plot graphs z-scores (normal scores) against your data set. A straight, diagonal line in a normal probability plot indicating normally distributed data. If the line is skewed to the left or right, it means that you do not have normally distributed data.
Which is the key output of probability plot Minitab?
Key output includes the p-value, the fitted distribution line, and the estimated percentiles. To determine whether the data follow the distribution, compare the p-value to the significance level. Usually, a significance level (denoted as α or alpha) of 0.05 works well.
When to reject null hypothesis in MINITAB tooltip?
The p-value is greater than the significance level of 0.05. Therefore, the scientist fails to reject the null hypothesis that the data follow a normal distribution. If you hold your pointer over the fitted distribution line of the graph in Minitab, a tooltip shows a table of percentiles and values.
What to do if p value is less than significance?
If the p-value is less than or equal to the significance level, the decision is to reject the null hypothesis and conclude that your data do not follow the specified distribution.
What is the significance level of the Minitab Express?
Usually, a significance level (denoted as α or alpha) of 0.05 works well. A significance level of 0.05 indicates that the risk of concluding the data do not follow a normal distribution—when, actually, the data do follow a normal distribution—is 5%.