Estimate by division ..70/9.24
2 answers:
Here we have to divide 70 by 9.24.
we can first covert the decimal 9.24 into fraction, shifting the decimal two units to the right and dividing by 100, we have
9.24 = 924/100
Now let us divide 70 by 924/100
in division of fraction we take reciprocal of second fraction and multiply it with first.
reciprocal of 924/100 is 100/924.
multiplying 70* 100/924, we have
converting into decimal we have
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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=
=
=
=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.