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Leviafan [203]
3 years ago
8

A GE Lightbulb is suppose to last for 1200 hours. In fact light bulbs of this type last only 1,185 hours with a standard deviati

on of 70 hours. What is the probability that a randomly selected light bulb will have an average life of at least 1,200?
Mathematics
1 answer:
Andre45 [30]3 years ago
8 0
This can be solved using the formula for t test which is = x - mu over standard deviation divided by the square root of the number of samples. In this case, it is 1185 - 1200 over 70 divided by square root of 100 which give us a value of 2.14 which is equal to .9839 in area. Only rarely, just over one time in a hundred tries of 100 light bulbs, would the average life exceed 1200 hours.
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Help plssssss!!!!!!!
In-s [12.5K]
For the first question asking about the slope 3/4 and y intercept -2 would be (y=0.75x-2) because 3/4=0.75 and the y intercept -2 is b and you’re just placing it into the formula y=Mx+b m=slope b=y intercept.
7 0
2 years ago
Suppose an isosceles triangle abc has a=pi/4 and b=c=4. What is the length of a^2?
Zanzabum

The law of cosines states that, if \alpha is the angle between sides b and c,

a^2 = b^2+c^2-2bc\cos(\alpha)

So, plugging our values, we have

a^2 = 16+16-2\cdot 4\cdot 4\cdot\cos\left(\dfrac{\pi}{4}\right)

This is equal to

a^2 = 32-32\cdot\dfrac{\sqrt{2}}{2} = 32-16\sqrt{2}

3 0
3 years ago
Solve for x. Enter the solutions from least to greatest. (x−1)^2−9=0
Leno4ka [110]

Step-by-step explanation:

(x−1)²−9=0

(x-1)²= 9

x-1 = ±√9

x-1 = ±3

x = 1-3=-2 or x=1+3=4

the solution = {-2,4}

6 0
2 years ago
25x = 125x + 3<br><br> x = −10<br> x = −9<br> x = −3<br> x = 3
ICE Princess25 [194]

Answer:

x=-9

Step-by-step explanation:

first you make the coefficients equal to each other by doing a common factor which in this case is 5. Then you have to do the variable for each time the common number is repeated which is 5^x * 5^x= 5^(x+3)*5^(x+3)*5^(x+3) This would make it equal to 5^2x=5^(3x+9). Since the non exponents are common factors you can get rid of them and solve for the exponent by doing 2x=3x+9. You solve that equation to get x=-9.

8 0
2 years ago
Am I correct? If so why?
babunello [35]

Answer: its correct

Step-by-step explanation: and its correct cuase its the answer you choose

7 0
2 years ago
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