Hello guys. This will be the second last blog that I am going to post this semester. It's been a long journey and I hope everyone enjoys the content ! In this blog, I will be using the DOE experimental data which we have obtained earlier from the DOE practical to determime the effect of stop angle on the distance travelled by the projectile.
Before we get started, I would like to introduce my team members. 1. Yu Han (Iron man): Run 1 & 3
2. Joel (Thor): Run 2 & 4
3. Brice (Captain America): Run 2 & 6
4. Myself (Black Widow): Run 4 & 8
5. Jian Lun (Hulk): Run 6 & 8
Each Avenger will be conducting hypothesis testing on different factors (Projectile weight and Stop angle) using different runs as stated above.
Some of the viewers might be wondering what hypothesis testing is????? Well, hypothesis testing refers to the formal procedures used by experimenters or researchers to accept or reject statistical hypotheses.
The ideal way to determine if a statistical hypothesis is true is by examining the entire population. Since that is often impractical, researchers usually examine only a random sample from the population. If the sample data is not consistent with the statistical hypothesis, the hypothesis is rejected.
There are a few occasions where hypothesis testing is applied to answer the questions.
CHECK THEM OUT !
Did Class 2B01 really fare better in the TST1 than Class 2B02 did?
Iron Man and Superman. Who is more powerful?
Is the new material as durable as the old one?
Is the new product performing better than the old one after changing the mechanism?
Without further ado, let's start our process by displaying the data collected from the DOE practical.
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The Question | To determine the effect of stop angle on the flying distance of the projectile |
Scope of the test | The human factor is assumed to be negligible. Therefore different user will not have any effect on the flying distance of projectile. Flying distance for catapult A is collected using the factors below: Arm length = 33.1 cm Projectile weight = 2.87 grams Stop angle = 50 degree and 70 degree |
Step 1: State the statistical Hypotheses: | State the null hypothesis (H0): The distance travelled by the projectile remains unchanged when the stop angle increases from 50 degree to 70 degree while the arm length and the weight of projectile are constant. State the alternative hypothesis (H1): The distance travelled by the projectile reduces when the stop angle increases from 50 degree to 70 degree while the arm length and the weight of projectile are constant. |
Step 2: Formulate an analysis plan. | Sample size is 16. Therefore t-test will be used. Since the sign of H1 is "<", a left tailed test is used. Significance level (α) used in this test is 0.05 (most commonly used) |
Step 3: Calculate the test statistic | State the mean and standard deviation of Run # 4 : Mean:140.3 cm Standard deviation: 3.33 State the mean and standard deviation of Run # 8: Mean: 110.4 cm Standard deviation: 0.92 Compute the value of the test statistic (t)  |
Step 4: Make a decision based on result | Type of test (check one only) 1.Left-tailed test: [ ✅ ] Critical value tα= - 1.761 2.Right-tailed test:[ __ ] Critical value tα= ______ 3.Two-tailed test:[ __ ] Critical value tα/2= ± ______   Compare the values of test statistics, t (-22.9), and critical value(s),tα (-1.761). Therefore, H0 is false as it falls into reject H0 region. |
Conclusion that answer the initial question | As H0 is false, H1 is then accepted. This indicates that the distance travelled by the projectile reduces when the stop angle increases 50 to 70 degree while the arm length and the projectile weight remain unchanged. |
Compare your conclusion with the conclusion from the other team members | Iron man's result: The distance travelled by the projectile will decrease when the projectile weight is increased (from 0.86g to 2.87g), while the arm length and stop angle remain constant. Thor's result: The distance travelled by the projectile reduces when the projectle weight is increased from 0.86g to 2.87g, while the arm length and stop angle remain constant. Captain America's result: The distance travelled by the projectile reduces when the stop angle increases from 50 degrees to 70 degrees while the arm length and stop angle remain constant. Hulk's result: (TBD) |
What inferences can you make from these comparisons? |
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Your learning reflection on this Hypothesis testing activity | This activity helps me recall what we have learnt and utilizes the concept of hypothesis testing.
After studying the design of experiment (DOE), I was able to determine the interaction effect between two factors and the significance of each factor with the aid of graph plotting on EXCEL. Now I have one more weapon in my arsenal when dealing with similar scenarios. Hypothesis testing enables me to solve the problem without using any software. Even though one could not directly rank the significance of factors, applying hypothesis testing provides a quick analysis of the data. Moreover, hypothesis testing allows us to evaluate the strength of our claim or assumption before implementing it in our data set. It provides a reliable framework for making any data decisions for our population of interest. As a maths enthusiast, studying hypothesis testing provides more opportunities for me to dig into statistical analysis which was not being covered in our engineering maths syllabus. The world we are living in currently is called "big data world" in which every move we make and everywhere we go will transform to data. Thus, having the knowledge on data or statistical analysis will elevate ourselves to a new level and make us stand out when pursuing certain careers. Lastly, I was able to develop my Microsoft Words skill during the learning activities as I was required to submit the practice questions in the form of PDF upon completion. There were a few occasions where I was unsure about how to insert symbols and apply equations function in Words. After spending some time watching the tutorial on YouTube, I managed to overcome all the challenges. In my opinion, this activity is going to play an important role in future modules such as Capstone Project and Internship perhaps. |
IF YOU ARE STILL HERE, CONGRADULATIONS!!! YOU HAVE MADE IT :) :) THIS IS THE END OF THIS BLOG
Spoiler alert!!!!!!!!! In the following blog, I will be showcasing something you might have never ever seen in your life. SO FASTEN YOUR SEATBELT AND GET READY TO WITNESS BRILLIANCE.
Peace out.
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