#Chi square test minitab software#

(b) What are the success rates of the three treatments in preventing cardiac events? (a) Use the information in the news article to make a two-way table that describes the study results. In the same period, seven of the 34 people in the exercise group and 12 out of the 40 patients in usual care suffered such events.36 In the next three years, only three of the 33 people in the stress management group suffered “cardiac events,” defined as a fatal or non-fatal heart attack or a surgical procedure such as a bypass or angioplasty. The article goes on to say: One group took a four-month stress management program, another underwent a four-month exercise program, and the third received usual heart care from their personal physicians. They were assigned at random to three groups. The 107 subjects all had reduced blood flow to the heart and so were at risk of a heart attack. If you conduct a statistical test using a significance level of 0.1, 0.05, or 0.01 (or any significance level greater than 0.000) and get a p-value of 0.000, then reject the null hypothesis.Stress and heart attack You read a newspaper article that describes a study of whether stress management can help reduce heart attacks. The Chi-Square Test is a hypothesis test that determines whether a statistically significant difference (aka variance) exists between two or more independent. Chi-squared tests are for categorical data. Ratio Chi-Square will result in slightly different answers.

#Chi square test minitab software#

Most software only display three decimal places, though, which is why the p-value shows up as 0.000. Introduction: For this lab we will be using the hypothesis testing steps to answer questions about several scenarios. The Pearson Chi-Square results from Minitab should match the answers in the book. Let O 1, O 2,, O r c denote the observed counts for each cell and E 1, E 2,, E r c denote the respective expected counts for each cell. In a summary table, we have r × c r c cells. Enter Service in the field For rows: column. To conduct this test we compute a Chi-Square test statistic where we compare each cell's observed count to its respective expected count.

Whether you use Microsoft Excel, a TI-84 calculator, SPSS, or some other software to compute the p-value of a statistical test, often times the p-value is not exactly 0.000, but rather something extremely small like 0.000000000023. Go to the Stat menu, click on Tables, and select Cross Tabulation and Chi-Square. Thus, he concludes that there is sufficient evidence to say that the true average weight of a tire is not 200 pounds. Since the p-value of 0.000 is less than the significance level of 0.05, the auditor rejects the null hypothesis. Upon conducting a hypothesis test for a mean, the auditor gets a p-value of 0.000. The alternative hypothesis: (Ha): μ ≠ 200 Example: Getting a P-Value of 0.000Ī factory claims that they produce tires that each weigh 200 pounds.Īn auditor comes in and tests the null hypothesis that the mean weight of a tire is 200 pounds against the alternative hypothesis that the mean weight of a tire is not 200 pounds, using a 0.05 level of significance.

Let’s walk through an example to clear things up. Since 0.000 is lower than all of these significance levels, we would reject the null hypothesis in each case. Common significance levels include 0.1, 0.05, and 0.01. Use Minitab to conduct a chi-square test of independence to determine if there is evidence of a relationship between beverage preference and biological sex. So, when you get a p-value of 0.000, you should compare it to the significance level. If the p-value is less than the significance level, we reject the null hypothesis. A new window named Cross Tabulation and Chi-Square pops up.

When you run a statistical test, whether it’s a chi-square test, a test for a population mean, a test for a population proportion, a linear regression, or any other test, you’re often interested in the resulting p-value from that test.Ī p-value simply tells you the strength of evidence in support of a null hypothesis. Steps to run a chi-square test in Minitab: Click Stat Tables Cross Tabulation and Chi-Square.