Answer:
Check the explanation
Step-by-step explanation:
Let X denotes steel ball and Y denotes diamond
= 1/9( 50+57+......+51+53)
=530/9
=58.89
= 1/9( 52+ 56+....+ 51+ 56)
=543/9
=60.33
difference = d =(60.33- 58.89)
=1.44
s12 = 1/9( 502+572+......+512+532) -9/8 (58.89)2
=31686/8 - 9/8( 3468.03)
=3960.75 - 3901.53
=59.22
s1 = 7.69
s22 = 1/9( 522+ 562+....+ 512+ 562) -9/8 (60.33)2
=33295/8 - 9/8 (3640.11)
=4161.875 - 4095.12
=66.75
s2 =8.17
sample standard deviation for difference is
s=![\sqrt{[(n1-1)s_1^2+ (n2-1)s_2^2]/(n1+n2-2)}](https://tex.z-dn.net/?f=%5Csqrt%7B%5B%28n1-1%29s_1%5E2%2B%20%28n2-1%29s_2%5E2%5D%2F%28n1%2Bn2-2%29%7D)
= ![\sqrt{[(9-1)*59.22+ (9-1)*66.75]/(9+9-2)}](https://tex.z-dn.net/?f=%5Csqrt%7B%5B%289-1%29%2A59.22%2B%20%289-1%29%2A66.75%5D%2F%289%2B9-2%29%7D)
= 
=7.93
sd = 
=
=7.93* 0.47
=3.74
For 95% confidence level 
=1.96
confidence interval is
=(1.44 - 1.96* 3.75 , 1.44+1.96* 3.75)
=(1.44 - 7.35 , 1.44 + 7.35)
=(-2.31, 8.79)
There is sufficient evidence to conclude that the two indenters produce different hardness readings.
Answer:
480
Step-by-step explanation:
Important Information:
A Book Has 12 Chapters.
The Mean length of the chapters is 40 pages.
Question to Answer:
How many total pages are there in the 12 chapters?
Explanation/Solution:
Let's assume that the total number of pages in the book is "x" pages.
To find the mean (average) we divide the total "x" by 12 because there are 12 chapters in the book, which would equal to 40.
=40
Multiply both sides by 12...
x = 480
Hence, The total number of pages in the 12 chapters is 480.
Answer:
Step-by-step explanation:
Subtract 15 from both sides of the equation.
Answer:
1∠22.5°, 1∠112.5°, 1∠202.5°, 1∠292.5°
Step-by-step explanation:
A root of a complex number can be found using Euler's identity.
<h3>Application</h3>
For some z = a·e^(ix), the n-th root is ...
z = (a^(1/n))·e^(i(x/n))
Here, we have z = i, so a = 1 and z = π/2 +2kπ.
Using r∠θ notation, this is ...
i = 1∠(90° +k·360°)
and
i^(1/4) = (1^(1/4))∠((90° +k·360°)/4)
i^(1/4) = 1∠(22.5° +k·90°)
For k = 0 to 3, we have ...
for k = 0, first root = 1∠22.5°
for k = 1, second root = 1∠112.5°
for k = 2, third root = 1∠202.5°
for k = 3, fourth root = 1∠292.5°
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