BLOG 4 Hypothesis Testing !

Hello people :) in this blog I will be performing hypothesis testing based on the results my group obtained in practical 3!!As Black Widow, I will be using run 4 and run 8 for my hypothesis testing

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 is collected using the factors below: Arm length = 33 cm Projectile weight = 2.08 grams Stop angle = 90 degree and 45 degree
Step 1: State the statistical Hypotheses	State the null hypothesis (H0): When the arm length is 33cm and the projectile weight is 2.08 grams, the flying distance travelled by the projectile using the stop angle of 90 degrees and 45 degrees will be the same. State the alternative hypothesis (H1): When the Arm Length is 33cm and the projectile weight is 2.08 grams, the flying distance travelled by the projectile using a stop angle of 90 degrees and 45 degrees will be different.
Step 2: Formulate an analysis plan	Sample size is less than 30. Therefore t-test will be used. Since the sign of H1 is ≠, two tailed test is used. Significance level (α) used in this test is 0.05.
Step 3: Calculate the test statistic	State the mean and standard deviation of Run #8: Mean, x̄8 = 84.0 Standard deviation, s8 = 1.83 n8 = 4 State the mean and standard deviation of Run #4: Mean, x̄4 = 83.5 Standard deviation, s4 = 3.32 n4 = 4
Step 4: Make a decision based on result	Type of test: Left-tailed test: [ ]  Critical value tα = Nil Right-tailed test: [ ]  Critical value tα = Nil Two-tailed test: [X]  Critical value t0.975 = ± 2.447 Since t=0.23, it is well within the acceptable region resulting in null hypothesis,H0 being accepted.
Conclusion that answer the initial question	Since H0 is accepted. we can conclude that at 33cm arm length and a projectile weight of 2.08 grams, the flying distance of the projectile does not differ when using either 90 degrees stop angle or 45 degrees stop angle . Thus, stop angle does not affect the flying distance of the projectile.
Compare your conclusion with the conclusion from the other team members	Jing Yue results shows me that at 28cm arm length and 45 degree stop angle, the flying distance of the projectile using 2.08grams and 0.86 grams projectile weight gives different flying distance. Thus, projectile weight has significant effect on flying distance. Yu Jie results are the same as Jing Yue which is that that at 33cm arm length and 45 degree stop angle, the flying distance of the projectile using2.08grams and 0.86grams projectile weight gives different flying distance. Thus, projectile weight has significant effect on flying distance. Mabelle results are the same as mine where stop angle does not have significant effect on the flying distance of the projectile.
What inferences can you make from these comparisons?	Based on the above comparisons, I can infer that stop angle does not affect the flying distance of the projectile.Secondly, I can infer that projectile weight significantly affects the flying distance of the projectile.

LEARNING REFLECTION

Hypothesis testing , let me start by sharing what I learnt. I learnt that this method gives us a systematic and structured approach to validate claims and hypotheses. It helps us to observe relationships and determine significance of the effects on our dependant variable. This method aids us in improving efficiency of an experiment or a product. Some of the mishaps I faced was trying figure out if my t value was within the acceptable range or not. I was also amazed that the type of test type we are using is based on how we phrase our alternative hypotheses.

The steps used in hypotheses testing was rather easy to follow for me however, it can be very tedious, it was just the calculations part where I was careless and used mean value instead of n in finding the sigma value. However, I have to ensure that the experiment runs done have to make sense and the data collected have to be reliable to prevent us from coming with a wrong conclusion on the hypothesis.

I believe this knowledge will be very helpful to me when I embark on my FYP in the future.