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:
3×(27-7) says to subtract 7 from 27 first, then multiply with 3; but 3×27-7 says to multiply 3 by 27 first ,then subtract 7.
The second bullet is the correct option
total = 2372* (1+0.045)^20=
2372*1.045^20=
2372 * 2.411714025= 5720.585
she will have 5720.59 in 20 years
So in matt's equation, he made a mistake in the a transision from line 2 to line 3
in line 2: -4(-2)2
in line 3: -4(4)
the mistake is that -2 times 2 is not equal +4 it is equal to -4
also from lines 5 to 6 he made a mistake in order of opperations (mulit division then addition and subtract)
line 5: -10+30/5
line 6: 20/5
so he first subtracted 10 then divided, he should have divided then subtracted
so the equation should have equaled
Karen used the correct (-) times (+) property and the order of operations
so Karen is correct and Matt is wrong.
Y + 18 = a(x + 3)^2
<span>0 + 18 = a(0 + 3)^2 </span>
<span>18 = 9a </span>
<span>2 = a
</span>
<span>y = 2(x + 3)^2 - 18 </span>
<span>0 = 2(x + 3)^2 - 18 </span>
<span>18 = 2(x + 3)^2 </span>
<span>9 = (x + 3)^2 </span>
<span>± 3 = x + 3 </span>
<span>-3 ± 3 = x </span>
<span>x = 0 or -6
</span>
<span>(0, 0) and (-6, 0)</span>