Below are tabulated a number of Rockwell G hardness values that were measured on a single steel specimen. Compute
1 answer:
Answer:
a) 48.408
b) 1.235
Step-by-step explanation:
a)
The average hardness value xbar can be computed as
xbar=sum of values/number of values
xbar=(46.5+46.9+49.4+50.3+49.8+48.8+47+47.7+48.3+49.4+47.8+49)/12
xbar=580.9/12
xbar=48.408 (rounded to 3 decimal places).
The average hardness value is 48.408.
b)
The standard deviation hardness value s can be computed as
x x-xbar (x-xbar) ²
46.5 -1.90833 3.64174
46.9 -1.50833 2.27507
49.4 0.99167 0.98340
50.3 1.89167 3.57840
49.8 1.39167 1.93674
48.8 0.39167 0.15340
47.0 -1.40833 1.98340
47.7 -0.70833 0.50174
48.3 -0.10833 0.01174
49.4 0.99167 0.98340
47.8 -0.60833 0.37007
49.0 0.59167 0.35007
Total 16.7692
s=1.235 (rounded to 3 decimal places)
The standard deviation hardness value is 1.235.
You might be interested in
This is adding two vectors, one magnitude 300 direction east, and one magnitude 100 direction 30 degrees northeast.
For the resulting sum we can use the Law of Cosines or just add up the components. Let's try it both ways.
Components first. In the east direction we have
300 + 100 cos 30° = 300 + 100(√3/2) = 386.60 miles per hour
In the north direction we have
0 + 100 sin 30° = 100 (1/2) = 50 miles per hour
So a total speed of
sqrt{386.6^2 + 50^2} = 389.82 miles per hour
Answer: 389.82
--------
OK let's try the Law of Cosines. We have sides 300 and 100 and included angle 150°.