How much extra money do you need this month to cover these emergencies??? Help
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Answer:
95% confidence interval for the mean efficiency is [84.483 , 85.517].
Step-by-step explanation:
We are given that in a sample of 60 electric motors, the average efficiency (in percent) was 85 and the standard deviation was 2.
So, the pivotal quantity for 95% confidence interval for the population mean efficiency is given by;
P.Q. = ~
where, = sample average efficiency = 85
= sample standard deviation = 2
n = sample of motors = 60
= population mean efficiency
<em>So, 95% confidence interval for the mean efficiency, </em><em> is ;</em>
P(-2.0009 < < 2.0009) = 0.95
P(-2.0009 < < 2.0009 ) = 0.95
P( <
<
) = 0.95
P( <
<
) = 0.95
<u>95% confidence interval for</u> = [
,
]
= [ ,
]
= [84.483 , 85.517]
Therefore, 95% confidence interval for the population mean efficiency is [84.483 , 85.517].
Answer:
x =4 ,y =4 and z =0 is the solution.
Step-by-step explanation:
We shall solve the equations using elimination method
In equation 2 and 3 we can see that coefficient of z in both equations are same with opposite sides , adding equations (2) and (3)
3y+5z = 12
y -5z = 4 adding the equations
___________
4y = 16
dividing both sides by 4
y =
y = 4
Plugging the value of y in equation 2 or equation 3 ,we get
3(4) +5z = 12
12+5z = 12
5z = 12-12 or 5z =0 gives z =0
plugging y =4 and z =0 in equation 1
2x+3(4)+ 0 = 20
2x+12 = 20
2x =20-12
2x = 8
x = 8 divided by 2 gives
x =4
therefore solution of the system is given by
x=4 , y =4 and z =0