Each year, a large warehouse uses thousands of fluorescent light bulbs that burn 24 hours per day until they burn out and are replaced. The lifetime of the bulbs is a normally distributed random variable with mean equal to 600 hours and standard deviation of 12 hours. The supplier of the light bulbs and the manager agree that any bulb whose lifetime is among the lowest 1% of all possible lifetimes will be replaced at no charge. What is the maximum lifetime a bulb can have (hrs) and still be among the lowest 1% of all lifetimes
Answer:
The maximum lifetime a bulb can have and still be among the lowest 1% of all lifetimes is 572 hours.
Step-by-step explanation:
Normal Probability Distribution:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
The lifetime of the bulbs is a normally distributed random variable with mean equal to 600 hours and standard deviation of 12 hours.
This means that [tex]\mu = 600, \sigma = 12[/tex]
What is the maximum lifetime a bulb can have (hrs) and still be among the lowest 1% of all lifetimes?
This is the 1st percentile of lifetimes, which is X when Z has a pvalue of 0.01, that is, X when Z = -2.327.
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]-2.327 = \frac{X - 600}{12}[/tex]
[tex]X - 600 = -2.327*12[/tex]
[tex]X = 572[/tex]
The maximum lifetime a bulb can have and still be among the lowest 1% of all lifetimes is 572 hours.
The talk-time battery life of a group of cell phone is normally distributed with a mean
of 5 hours and a standard deviation of 15 minutes.
b) What percent of the phones have a battery life between 4.5 hours and 5.25
hours? (include 1 decimal place WITHOUT the % sign)
Answer:
Step-by-step explanation:
What is it help
Approximately 47.72% of phones have a battery life of between 4.5 and 5.25 hours.
What is standard deviation?A standard deviation (or σ) is a measure of how dispersed the data is in relation to the mean. Low standard deviation means data are clustered around the mean, and high standard deviation indicates data are more spread out.
here, we have,
To determine the percentage of phones with a battery life between 4.5 hours and 5.25 hours, we need to find the area under the normal curve between those two points.
To do this, we can standardize the lower and upper limits of the range and use a table of the normal distribution to find the area.
The lower limit of the range, 4.5 hours, is 0.25 hours less than the mean of 5 hours. Since the standard deviation is 15 minutes, which is equal to 0.25 hours, the lower limit is 0.25 standard deviations below the mean.
The upper limit of the range, 5.25 hours, is 0.25 hours more than the mean of 5 hours. Since the standard deviation is 15 minutes, which is equal to 0.25 hours, the upper limit is 0.25 standard deviations above the mean.
The area under the normal curve between the lower and upper limits is therefore the area under the normal curve between -0.25 and 0.25 standard deviations.
Using a table of the normal distribution, we find that the area under the normal curve between -0.25 and 0.25 is approximately 0.4772.
Thus, about 47.72% of phones have a battery life between 4.5 hours and 5.25 hours.
Learn more about the standard deviation here:
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r = 3.7 m.
Calculate the circumference of the circle.
Answer: 23.25m
Step-by-step explanation:
C=2πr=2·π·3.7≈23.24779m
Animal house rescue is holding a fundraiser raffle. they sell 2,980 tickets for $1 each for a prize telescope valued at $425. what is the expected gain or loss to a participant purchasing ten tickets
A)$4,240.00 gain
B)$8.57 loss
C)$0.86 loss
D)$12.85 gain
Answer: The answer is C, hope I helped :)
Step-by-step explanation:
A purchase of 10 tickets is at an expected loss of $0.857 to the person.
Option B) $8.57 loss is the right choice.
What do we mean by Expected Gain or Loss?The expected gain or loss is a weighted average of the probability of the different gains or losses and the gains or losses.
How do we solve the given question?We are asked to calculate the expected gain or loss for a participant who purchases 10 tickets for a raffle costing $1 each, with a prize of a telescope valued at $425. We are told that a total of 2980 tickets have been sold.
First, we calculate the expected gain or loss on 1 ticket,
= 425*(1/2980) + (-1)(1)
= 0.1426174496 - 1
= -0.857382550.
∴ A purchase of 1 ticket is at an expected loss of $0.857
Now, we multiply this by 10 to get the expected gain or loss for the person with 10 tickets.
= -0.857382550*10 = -8.57382550
∴ A purchase of 10 tickets is at an expected loss of $0.857 to the person. Option B) $8.57 loss is the right option.
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A bus is traveling at a constant speed. If the bus travels 15 miles in 1/3
of an hour,
how many miles will the bus travel in one hour?
evious
NO
HC
US
Answer:
Step-by-step explanation:
5 mph
x dvided 8 = 9
what is value of x
Answer:
72
Step-by-step explanation:
72/8 = 9
Answer:
x=72
Step-by-step explanation:
Step- by- step Explanation
Paul purchased a new fish tank, represented by the diagram below.
The height, h, of the tank is 3 feet, and the width, w, is 6 feet longer than the length, l. The volume of the tank (V=lwh) is 60 ft^3.
Write an equation that could be used to calculate the length of the tank.
Determine the exact length of the tank in simplest radical form.
Answer: l=-3+square root of 29
Step-by-step explanation:
I got this on my math homework
i need to know the surface area of both 1 and 2 please
Answer:
1. 142 in.²
2. 190 cm²
Step-by-step explanation:
Both solids are rectangular prisms.
Surface area of a rectangular prism = 2(LW + LH + HW)
1. L = 7 in.
W = 3 in.
H = 5 in.
Plug ok the values into the formula
Surface area = 2(7*3 + 7*5 + 5*3)
= 142 in.²
2. L = 10 cm
W = 3 cm
H = 5 cm
Plug ok the values into the formula
Surface area = 2(10*3 + 10*5 + 5*3)
= 190 cm²
Grayson bought a rectangular waste basket that is 3 1/2 feet long, 3/4 foot wide, and 1 foot high.
Answer:
cool and whats the question
Step-by-step explanation:
ILL MARK U BRAINLESS IF YOU HELP ME PLEASE!!!!!
PLEASE HELPI DON’T UNDERSTAND
X= -3 this solution is extraneous
X= 5 this solution is valid
Struggling with these last two. Thanks so much!!
Answer:
1. C
2. D
Step-by-step explanation:
1. first find the slope by using the formula (y2-y1)/(x2-x1). We need to find the equation for CE so use points C (0, 1) and E (5, 5). (5-1)/(5-0) = 4/5, which is the slope. from there u can tell that the answer is the third choice, which let's say is C, because the y intercept of the line is 1.
2. Do the same thing except with points A (-5, 1) and D (0, 6). (6-1)/(0-(-5)) = 1
The y intercept is 6 because that is where the line intersects the y axis, or where x is 0.
so the equation is y=x+6, which is just the last option, let's say D, but just rearranged
If p is inversely proportional to the square of q, and pis 24 when q is 11,
determine p when q is equal to 2.
Answer:
726
Step-by-step explanation:
Here p = k / q², and 24 = k / 121, or k = 2904
Then p = 2904 / q²
If q = 2, p = 2904 /4 = 726
Answer:
p = 12 × 11²
Step-by-step explanation:
By question,
=> p ∝ 1/q²
=> p = k/q²
When p is 24 and q is 11=> 24 = k/11²
=> k = 24 * 11²
When q is 2 ,=> p = k/q²
=> p = 24*11²/2
=> p = 12 × 11²
Greg made the dart board shown. It is divided into equal sections. A dart is randomly thrown and lands on the board.
5
1
2
3
3
2
4
1
5
What is the probability that a dart will land on a section marked with the number 1?
O A 5%
B. 10%
O C. 20%
OD. 25%
O E SOS
SRESET
Gianna Faith Russell, ID#***93
Question #22
Growth: Math 6+ MD 2011
A 407
1:24 PM
5/10/2021
Type here to search
RI
Answer:
Step-by-step explanation:
10
Fred has a jug that contains
750 milliliters of milk. How many
liters of milk are in the jug?
Answer:
.75 liters
Step-by-step explanation:
add a decimal point at the end of 750 and move it 3 places to the left because mili is one thousandth of a liter
help please help me
Answer:
given the way its said i say sudden.
Suppose we have two independent, normally distributed, populations and we draw a random sample from each population. For population A, we drew a sample of 13 and found the mean to be 17 with a standard deviation of 4. For population B, we drew a sample of 12 with a mean of 19 and a standard deviation of 3. We want to determine if the treatments result in the same effect. Show all work.
Answer:
Since the calculated value of z= -1.421 does not lie in the critical region z >
- 1.96 the null hypothesis is accepted and it is concluded that the treatments result in the same effect.
Step-by-step explanation:
1) Let the null and alternate hypothesis be
H0: μa − μb = 0 the treatments result in the same effect
against the claim
Ha: μa − μb ≠ 0 the treatments do not result in the same effect
2) The significance level is set at 0.05
3) The critical region is z = ± 1.96
4) The test statistic
Z= x1`-x2`/ sqrt [( s1²/n1+ s2²/n2)]
Here
x1`= 17 s1= 4 n1= 13
x2`= 19 s2= 3 n2= 12
5) Calculations
Z= x1`-x2`/ sqrt [( s1²/n1+ s2²/n2)]
z= 17-19/sqrt [( 16/13+ 9/12)]
z= -2/1.40739
z= -1.421
6) Conclusion
Since the calculated value of z= -1.421 does not lie in the critical region z >
- 1.96 the null hypothesis is accepted and it is concluded that the treatments result in the same effect.
Write a system of linear equations for the graph below.
Answer:
-3/-2
Step-by-step explanation:
because (x,y) the x coordinate is -3 and the y coordinate is -2
2,649 divided by 55 please help
Answer:
49.1636363636
Step-by-step explanation:
What is the slope of the line
Answer:
3
Step-by-step explanation:
I need he answer pls answer fast answer don’t scam
Answer:
30 ft²
Step-by-step explanation:
Area of trapezium = 1/2 (a + b)h
a = 6 ft , b = 9 ft , h = 4 ft
Area = 1/2 (6 + 9) 4
= 30 ft²
Answer:
D
Step-by-step explanation:
Help meeeeeeeeeeeeeeeeeeee
Answer:
Dependent
Step-by-step explanation:
When the probability is AND, it is dependent. You *have* to get the A outcome for A and B to be valid.
PLEASE ANYONE HELP! DONT ANSWER IF UNSURE PLEASE
Answer:
length 5cm, width 4cm, door width 2/5cm or. 4cm, length 10 ft, width 7.5 ft
what are the measures of 7 and 2 ? Explain please
Answer:
angle 2 is 99
angle 7 is 81
Step-by-step explanation:
Angle 2 and the angle we are given are congruent because they are vertical.
Angle 7 and the angle we are given form a line, so they add up to 180.
180-99 = 81
Solve 1/3(3.2×1.4)2.8
Simplify your answer
Answer:
4.181
Step-by-step explanation:
1/3 (3.2×1.4) 2.8
1/3 ( 4.48) 2.8
1/3 (4.48 × 2.8)
1/3 × 12.544
= 4.181
Help pls!Pls and ty!
Answer:
a
Step-by-step explanation:
HELP me with this work please
Answer:
135in^3
Step-by-step explanation:
Enter the values for the highlighted variables to
complete the steps to find the sum:
az
b =
3x 9
+
2x - 6 6 - 2x
CE
d =
3 x
9
+
2x-6 al 2x-6)
3x b.
+
2x-6 2x - 6
3х – с
2x-6
d{x - e)
f(x-3)
= 9
e =
f=
III
g=
DONE
Answer:
a = - 1
b = - 9
c = 9
d = 3
e = 3
f = 2
g = 3/2
Step-by-step explanation:
For a;
6 - 2x = - (2x - 6)
For b;
-1 * 9 = - 9
For x ;
3x + (-9) = 3x - 9
3x - 9 = d(x - e)
Factorizing :
3(x - 3)
d = 3 ; e = 3
2x - 6 = f(x - 3)
Factorize :
2x - 6 = 2(x - 3)
3(x - 3) / 2(x - 3)
g = 3/2
a coffee shop sells coffee beans by the pound. A container hold 16 kilograms of coffee beans. For every 1 kilogram, there are approximately 2.2 pounds
Answer:
23.6
Step-by-step explanation:
Answer: 23.6
Step-by-step explanation:
A $1,200 computer is losing value at a rate of 22% per year; 2 years
Answer:
$730.08
Step-by-step explanation:
22% = 0.22
1 - 0.22 = 0.78
Value after 2 years
v = 1200(0.78)²
v = 730.08
$730.08