Using the T-Test and ANOVA

Data Analysis: t-Test and ANOVA
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Data Analysis: Hypothesis Testing
This project used the Sun Coast Remediation dataset to perform t-test and ANOVA hypothesis testing to assess the differences between variables or groups. The data analysis was conducted using the data analysis Toolpak in Excel.
Independent Samples t-Test: Hypothesis Testing
This parametric test is used to test the mean differences between two independent groups (Arkkelin, 2014). In addition, this project carried out an independent t-test to assess whether there is a significant difference between the safety training programs of Group A employees who were trained using the current program (the prior training, IV1) and Group B employees who were trained using a new program (revised training, IV2).
The hypotheses are as follows:
Ho4: There is no statistically significant difference in mean values of the DV between Group A (IV1), Prior Training, and group B (IV2), Revised Training.
Ha4: There is a statistically significant difference in mean values of the DV between Group A (IV1), Prior Training, and group B (IV2), Revised Training.
The table below shows the results from Excel
t-Test: Two-Sample Assuming Unequal Variances


 

Prior Training

Revised Training

Mean

69.7903

84.7742

Variance

122.00450

26.9646

Observations

62

62

Hypothesized Mean Difference

0


df

87


t Stat

-9.6666


P(T<=t) one-tail

9.699E-16


t Critical one-tail

1.6626


P(T<=t) two-tail

1.94E-15


t Critical two-tail

1.9876

 

Table SEQ Table \* ARABIC 1: Independent t-Test
The results indicate that the average values are lower for Group A employees who were trained using the current program (the prior training). Additionally, the results also show a p-value of 1.94 x 10-15 (two-tailed), which is less than 0.05 alpha level. Therefore, we reject the null hypothesis and accept the alternative hypothesis that there is a statistically significant difference in mean values of the DV between Group A (IV1), Prior Training, and group B (IV2), Revised Training. The company should consider replacing the prior safety training program with the revised program since the mean scores from the training show improvement.
Dependent Samples (Paired Samples) t-Test: Hypothesis Testing
A Dependent sample t-test is used to compare the means of two measurements drawn from the same object or individual (LibGuides, 2021). In a dependent t-test, a dependent variable is measured for one group both before and after exposure to an independent variable to determine if statistically significant differences exist. This project carried out a dependent sample t-test to assess whether the blood lead levels had increased while employees conducted lead remediation at the job sites. The data used was from forty-nine employees. The null and alternative hypotheses formulated are as follows:
Ho5: There is no statistically significant difference in the lead levels in the blood, pre-exposure and post-exposure.
Ha5: There is a statistically significant difference in the lead levels in the blood, pre-exposure and post-exposure.
The results from Excel are shown in the table below



 

Pre-Exposure μg/dL

Post-Exposure μg/dL