Statistical Methods in Healthcare Assignment #7 15 points Answer the following questions in narrative format: 1. Discuss when it is appropriate to use the paired t-test and the Wilcoxon matched-pairs signed-rank test. (2 points) The paired t-test is a parameter test that compares the means between two correlated pair groups. The paired t-test is used when two measures of the same interest are taken on the same participant at two different points in time. This participant is serving as their own control. The paired t-test can also be used when there are two measurements of the same interest that is measured at the same time, where one person has received the characteristic of interest and one person who has not received the …show more content…
The data that is required for the Wilcoxon test should be two measures of the same characteristic of interest taken on a participant and matched control. The data should be two measures of the same interest taken on the same participant at two different points in time. Interval or ratio scale can be used. The sample size should be small and at least five pairs of measurements. 3. Detail the steps in computing the Paired t-test with a brief discussion specific to the important aspects of each step. (6 points) According to Kellar and Kelvin (2013), “There are six steps in computing the paired t-test”, (p. 131-136). The first step is stating the null and alternative hypotheses. The null Hypotheses states that there will be no difference in the pretest and posttest characteristic of interest. In the alternative hypotheses, the posttest characteristic of interest will be different from the mean pretest characteristic of interest. The second step is defining the significance level, determining the degrees of freedom and finding the critical value. The a-level shows that for a result to be statistically significant, it cannot occur more than the a-level percentage of time by chance. The critical value can be obtained by using the t-test table. The degrees of freedom is located down the row of the t-table. The critical value result is the point where the a-level and degrees of
So, we should reject the null hypothesis H0. At a 0.05 level of significance level, we conclude that there is a significant difference between the average height for females and the average height for the males.
Create a research hypothesis tested using a one-tailed test and a research hypothesis tested using a two-tailed test.
When you perform a test of hypothesis, you must always use the 4-step approach: i. S1:the “Null” and “Alternate” hypotheses, ii. S2: calculate value of the test statistic, iii. S3: the level of significance and the critical value of the statistic, iv. S4: your decision rule and the conclusion reached in not rejecting or rejecting the null hypothesis. When asked to calculate p–value, S5, relate the p-value to the level of significance in reaching your conclusion.
If researchers conducted 9 t-tests on their study data. What alpha level should be used to determine significant differences between the two groups in the study? Provide your calculations.
The t-test is a parametric analysis technique used to determine significant differences between the scores obtained from two groups. The t-test uses the standard deviation to estimate the standard error of the sampling distribution and examines the differences between the means of the two groups. Since the t-test is considered fairly easy to calculate, researchers often use it in determining differences between two groups. When interpreting the results of t-tests, the larger the calculated t ratio, in absolute value, the greater the difference between the two groups. The significance of a t ratio can be determined by comparison with the critical values in a
One-sample t-test are used in the parametric test which analyzes the means of populations. The t-test for independent groups are statistics that relates difference between treatment means to the amount of variability expected between any two samples of data within the same population (Hansen & Myers, 2012). Critical values are used in significant testing provide a range of t distribution that is used in whether a null hypothesis is rejected. Based on the data below as the level of significance is at .05, thus the critical values would fall under ±1.860 and the t value for this is 1.871 would suggest for the null to be rejected as it is greater than the critical value (Privitera, 2015, p. 267). Based on the population mean of 70 there was a mean difference of
The t value that is the smallest represents health responsibility and is t = 1.03. It is not statistically significant, as the analyses did not indicate it to be so (i.e. no * next to the value).
1. In an experiment involving matched pairs, a sample of 15 pairs of observations is collected. The degree of freedom for the t statistic is 14. true
A two-sample t-test is a hypothesis test that is used to compare if there is a difference between two groups. One of the first steps in a two-sample t-test is to establish a hypothesis. The two-sample test helps to answer hypotheses that question how the results of one group that may already be in place compare to the results of another group that is new. The two-sample hypothesis test is a common hypothesis test used in many industries.
The Bonferroni post-hoc analysis was used to test the pairwise differences of the adjusted means and the results were obtained as indicated in table 4 below.
Since this study lacked statistical power in determining significant correlations due our small sample size (N = 62), we emphasize the effect sizes of our results using Cohen’s d. We utilized independent samples t-tests
Assumption 2 of the t test is that there will be independence of observation. Here, a participant can only be a member of the male group or the female group; this cannot overlap and a person can only be assigned to one group. This will not be tested via a visual component, as this assumption is based on setting up the research correctly.
After the process had taken place of gathering all the required measurements we then carried out a statistical analysis which included the mean averages, the standard deviation and finally the t test using the primary data we had gathered. The software used was OpenOffice.org Calculator, this software is very similar to that of Microsoft Excel.
Answer (b): The t tests tell us if the predictor variable has a significant linear association with the outcome variable or not. The alpha value of 0.05 is used; if the value of
A one sample t test compares the mean of one group against a given, known value. For example, comparing the mean height of 10 students to value 165 cm.