Hypothesis Testing

HYPOTHESIS TESTING TASK FOR INDIVIDUAL BLOG

For this assignment, you will use the DOE experimental data using the CATAPULT that you have conducted during the practical. You will use FULL FACTORIAL DATA. You are free to express yourself in your blog, but the table provided on page 2 to 7 must be followed.

DOE PRACTICAL TEAM MEMBERS (fill this according to your DOE practical):

1. Lee Yeung Juen (Iron Man)

2. Mavis Chin (Thor)

3. Isabelle (Captain America)



4. Alvin Chuah (Black Widow)

 

Data collected for FULL factorial design using CATAPULT A (fill this according to your DOE practical result):


Iron Man will use Run #1 and Run#3. To determine the effect of projectile weight.

Thor will use will use Run #2 and Run#4. To determine the effect of projectile weight.

Captain America will use Run #2 and Run#6. To determine the effect of stop angle.

Black Widow will use Run #4 and Run#8. To determine the effect of stop angle.

Hulk will use Run #3 and Run#5. To determine the effect of projectile weight


The QUESTION

To determine the effect of ___projectile weight___ 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 =  _25___cm

Projectile weight = __20___ grams and __0.85____ grams

Stop angle = __15___ degree

 

Step 1:

State the statistical Hypotheses:

State the null hypothesis (H0):

The projectile weight has no significant effect on the flying distance of the projectile.

 

 

State the alternative hypothesis (H1):

The projectile weight has a significant effect on the flying distance of the projectile.

 

 

 

 

 

Step 2:

Formulate an analysis plan.

Sample size is _n=8__ Therefore t-test will be used.

 

 

Since the sign of H1 is __, a 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 # _1_:

Mean = 114.1 cm

Standard deviation = 2.55 cm

 

 

State the mean and standard deviation of Run #_3_:

Mean = 94.5 cm

Standard deviation = 5.46 cm 

 

Compute the value of the test statistic (t):

v = 8 + 8 - 2

   = 14




 

Step 4:

Make a decision based on result

Type of test (check one only)

1.     Left-tailed test: [ __ ]  Critical value tα = - ______

2.     Right-tailed test: [ __ ]  Critical value tα =  ______

3.     Two-tailed test: [ _v_ ]  Critical value tα/2 = ± __2.145____

 

Use the t-distribution table to determine the critical value of tα or tα/2



 

Compare the values of test statistics, t, and critical value(s), tα or ± tα/2

tα/2 = ± 2.145

t = ± 8.6054


 

Therefore Ho is __rejected___.

 

 

Conclusion that answer the initial question

 

Since H0 is rejected, His accepted. This tells us that the projectile weight has a significant effect on the flying distance of the projectile.

 

 

 

 

Compare your conclusion with the conclusion from the other team members.

 

My other group mate, Mavis Chin (Thor), did hypothesis testing for runs 2 and 4. Our conclusions are the same, Ho is rejected and H1 is accepted, suggesting that the projectile weight has a significant effect on the flying distance of projectile.

What inferences can you make from these comparisons?

 

For runs 2 and 4, Factor A, arm length, is positive. For runs 1 and 3, the factor is negative. Both tests result in Ho being rejected and H1 being accepted, however, a negative factor A produces a test statistic value of ± 8.6054 while a positive factor A produces a value of ± 3.085. This shows us that a change in factor A results in a significant change in the test statistic, there is a significant interaction between factors A and B.


Your learning reflection on this Hypothesis testing activity

 

 

The hypothesis testing activities have taught me a better way to verify my hypothesis for experiments. This will be very important for my internship and final-year project as I would be carrying out many experiments with a myriad of data sample sizes. With knowledge in hypothesis testing, I would be able to analyse the results I've collected with minimal errors and produce more reliable work.


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