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Statistic Analysis : T Test

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Statistic Analysis: T-test
A t-test is an analysis of two populations means through the use of statistical examination; the two samples are commonly small sample, testing the difference between the samples when the variances of two normal distributions are not known. For instance, in this study, a t-test could be conducted to compare the mean of velocity in grit 80 and that in grit 120 in experiment 1, to see whether there is a significance difference between their means (Starnes, 2010).
In the data analysis of this study, GraphPad Software is used to visualize the data. This tool is available at https://www.graphpad.com/quickcalcs/ttest1.cfm. Data will be input to the tool on the website to make a comparison. To do so, select unpaired …show more content…

T Test Results of Experiment 2– Testing Humidity
T Test
0g & 5g
0g & 15g
5g & 15g
Mean A-B
0.0001723
-0.00128359840
-0.00145588700
P value
0.7710
0.1137
0.0687
95% Confidence Interval
(-0.00114712019, 0.00149169739)
(-0.00295032588, 0.00038312908)
(-0.00305289218, 0.00014111818)
Result
NOT statistically significant
NOT statistically significant
Not quite statistically significant

Table 10. T Test Results of Experiment 3– Testing Component
T Test
200g & 100g
200g & 50g
100g & 50g
Mean A-B
-0.0004777
-0.0013187
-0.0008410
P value
0.0017
0.0004
0.0064
95% Confidence Interval
(-0.00071545658, -0.00023990862)
(-0.00183650526, -0.00080088874)
(-0.00137064668, -0.00031138212)
Result
Very statistically significant
Extremely statistically significant
Very statistically significant Data Visualization
In order to make the result of the experiment and the statistics more direct and easier to understand, visualization of data in graphs will be used in this part to help better understand and interpret the trend of the effect of each independent variables on their corresponding dependent variables.
Figure 5. Plot of Substrate Granularity vs. Velocity

Figure 6. Plot of Substrate Humidity vs. Velocity

Figure 7. Plot of Substrate Component vs. Velocity

Conclusion & Discussion
Overall, this experiment studies the influence of roughness, humidity and components on the behavior of earthworms. To test the impact of these factors, three experiments are

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