The shear strength of each of ten test spot welds is determined, yielding the fo
ID: 3224741 • Letter: T
Question
The shear strength of each of ten test spot welds is determined, yielding the following data (psi):
(a) Assuming that shear strength is normally distributed, estimate the true average shear strength and standard deviation of shear strength using the method of maximum likelihood. (Round your answers to two decimal places.)
(b) Again assuming a normal distribution, estimate the strength value below which 95% of all welds will have their strengths. [Hint: What is the 95th percentile in terms of and ? Now use the invariance principle.] (Round your answer to two decimal places.)
? psi
Explanation / Answer
Sample A
X-Xbar
(X-Xbar)2
362
-17.9
320.41
392
12.1
146.41
415
35.1
1232.01
389
9.1
82.81
362
-17.9
320.41
358
-21.9
479.61
375
-4.9
24.01
409
29.1
846.81
367
-12.9
166.41
370
-9.9
98.01
Total =3799
0
3716.9
Sample mean µ = 3799/10 =379.9
Sample S.D = sqrt( 3716.9/10)
= 19.2793
Sample A
X-Xbar
(X-Xbar)2
362
-17.9
320.41
392
12.1
146.41
415
35.1
1232.01
389
9.1
82.81
362
-17.9
320.41
358
-21.9
479.61
375
-4.9
24.01
409
29.1
846.81
367
-12.9
166.41
370
-9.9
98.01
Total =3799
0
3716.9
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.