The length of life of oil-drilling bits depends upon the types of rock and soil that the drill encounters, but it is estimated that the mean length of life is 55 hours. An oil exploration company purchases drill bits that have a length of life that is approximately normally distributed with mean equal to 55 hours and standard deviation equal to 9.1 hours.
What proportion of the company’s drill bits will have to be replaced after more than 90 hours of use?

Answers

Answer 1

Answer:

"0.9999" is the correct solution.

Step-by-step explanation:

The given values in the question are:

Mean,

= 55

Standard deviation,

= 9.1

Now,

⇒ [tex]z=\frac{X-mean}{sd}[/tex]

By putting the values, we get

⇒    [tex]=\frac{90-55}{9.1}[/tex]

⇒    [tex]=\frac{35}{9.1}[/tex]

⇒    [tex]=3.8461[/tex]

hence,

[tex]P(X<90)[/tex]

= [tex]P(Z<3.8461)[/tex]

= [tex]NORMSDIST(3.8461)[/tex]

then the value will be:

= [tex]0.9999[/tex]


Related Questions

Can someone solve these for me?

Answers

Answer:

In order of pictures,

Picture #1: 230

Picture #2: 140

Picture #3: 9.9

Picture #4: 13.5

Picture #5: 7.07

Step-by-step explanation:

I am not entirely sure that 3 - 5 are correct, but I know that 1 and 2 are correct. I am sorry if they are incorrect.

Hope that this helps!

List two pairs of angles in square CDFG that are complementary

Answers

Answer:

1st pair:  ∠C + ∠M

2nd pair: ∠G + ∠M

Step-by-step explanation:

Insert the greater than, less than, or equal sign (>, <, or =) to make each statement true.
a. 45⁄45 ____1
b. 1____ 6⁄3
c. 2⁄7 ____1
d. 64⁄23 ____1

Answers

Answer:

a. 45/45 = 1

b. 1 < 6/3

c. 2/7 < 1

d. 64/23 > 1

Psychologists in Montreal and Toronto conducted a study to determine if babies show any preference for speech over general noise.1 Fifty infants between the ages of 4-13 months were exposed to both happy-sounding infant speech and a hummed lullaby by the same woman. Interest in each sound was measured by the amount of time the baby looked at the woman while she made noise. The mean difference in looking time was 27.79 more seconds when she was speaking, with a standard deviation of 63.18 seconds. Perform the appropriate test to determine if this is sufficient evidence to conclude that babies prefer actual speaking to humming.

Required:
State the null and alternative hypotheses.

Answers

Answer:

H0 : μ1 - μ2 = 0

H1: : μ1 - μ2 ≠ 0

we reject the Null and we conclude that babies prefer actual speaking to humming.

Step-by-step explanation:

H0 : μ1 - μ2 = 0

H1: : μ1 - μ2 ≠ 0

Mean difference, d = 27.79

Standard deviation of difference, Sd = 63.18

Sample size, n = 50

The test statistic :

d / (Sd / √n)

Test statistic :

27.79 / (63.18 / √50)

27.79 / 8.9350012

= 3.11

Using the Test statistic score, we can obtain the Pvalue

Using the standard normal table ;

Pvalue = P(x<-Z or x>Z) = 0.0018709

Pvalue is very low

Pvalue < α ; Hence, we reject the Null and we conclude that babies prefer actual speaking to humming.

help help exponents help

Answers

Answer:

3

Step-by-step explanation:

The base is the number below the exponent.

In a store 8/300 of the shirts are yellow and 86/600 Are orange what percent of the shirts are not yellow or orange

Answers

Answer:

83%

Step-by-step explanation:

8/300 = 16/600

86 + 16 = 102

that leaves 498 that are not yellow or orange

so, 498/600 = 0.83 or 83%

Please help me please is it 2 or 4

Answers

Answer:

its 4

Step-by-step explanation:

PLS help asap bt 1230 pt help thank you will brainliest

Answers

Answer:

85

Step-by-step explanation:

So you train of though might lead you to soemthing like this: it must be 90 degrees, since that looks like a 90 degree triangle, and there are 180 degrees in a line. So 90 degrees and 90 degrees make up the 180.

That is exactly what I though.

But, its a bit different from that. We do not know for sure that its a 90 degree traingle. Depending on the angle of the traingle, the outcome of the mystery number is different.

So, to find the angle of the trainge, lets take our 155 degree line.

Now, this is just a simple line. We know the line is 180, and that the other number must add onto 155 to make 180:

180-155=missing angle

=

25. So we know that the smallest angle of the traingle is 25.

We also know that a traingle has a total of 180 degrees.

We can add the 60 degrees and our new 25 degrees, subtract if from 180, and we will get our last angle of the traingle we need to solve:

60+25

=

85

Now subtract it from 180:

180-85

=

95

So that last angle of the traingle is 95.

Now, we need to solve the missing angle of the line that will give us the answer.

Again, we know the line has to be 180, so lets subtract 95 from that:

180-95

=

85

So we know that the missing angle answer is 85!

I hope this isnt too confusing and helps! :)

A farmer would like to estimate the mean amount of

milk produced per day by his 300 cows. He selects a

random sample of 15 cows and records the amount of

milk produced in gallons) by those cows. The dotplot

shows the data. Given that all of the recorded values are integers, what is the value of the standard error of the mean?

0.765

0.792

2.267

2.346

Answers

Answer:

0.765

Step-by-step explanation:

The dot plot shows the data

x= 20,21,22,23,24,24,25,25,25,26,26,27,28,29,31

The mean x`= ∑x/n =20+21,+22,+23,+24,+24,+25,+25,+25+,26+,26+,27+,28+,29+,31/15= 376/15

=25.067

where n is the sample size= 15

The standard deviation is σ=2.96

( using calculator)

The standard error is calculated as

SE= σ/√n

SE= 2.96/√15

SE= 0.765

Find the missing angle.

Answers

Answer:

=180-50-70

=50

Step-by-step explanation:

=180-50-70

50

y
B (7,-3)
C(6,-)
A (4,-9)
What is the y-coordinate of point C?
OA – 4
OB. –S
C. -6
D.-7

Answers

Answer:

c, -6

I hope this helps you

3. Write an equation of the line that passes through (2, 3) and is perpendicular to y=-1/2x - 5

Answers

Answer:

y=2x-1

Step-by-step explanation:

A line that is perpendicular has a slope that is a negative reciprocal of the given equation. The slope of the given equation is -1/2, so the negative reciprocal would be 2.

Then, using slope-intercept form, plug in the point values (2,3) into the equation and solve for b.

y=mx+b

y=2x+b

3=2(2)+b

-1=b

Therefore the equation is y=2x-1

I need help with this problem can you please show the work

Answers

Answer:

48 degrees

Step-by-step explanation:

inscribed angle is always equal to the measure of the arc

12 ly
Which statement is true regarding the functions on the
graph?
10
8
-6
4
919
Of(6) = g(3)
O f(3) = g(3)
Of(3) = g(6)
Of(6) = g(6)
-6-
2
3 4 5 6 x
4 -3 -2 -12
- fix
-6
-8
-10
-12

Answers

Answer: f(3)=g(3)

Step-by-step explanation:

The graphs intersect at x = 3.

The statement "f(6) = g(3)" is true.The correct option is A.

What is a graph?

A graph is a structure that amounts to a set of items where some pairs of objects are in some manner "related" in discrete mathematics, more specifically in graph theory.

From the graph, we can see that the value of f(6) is 2, and the value of g(3) is also 2.

The statement "f(3) = g(3)" may or may not be true, as we do not know the values of f(3) and g(3) from the graph.

The statement "f(3) = g(6)" is not true, as the value of f(3) on the graph is -2, and the value of g(6) is 4.

The statement "f(6) = g(6)" is also not true, as the value of f(6) on the graph is 2, and the value of g(6) is 4.

To know more about the graph follow

https://brainly.com/question/21713905

#SPJ7

Which shows the best path to find the number of centimeters in 1 yard?
yards -> inches -> centimeters
yards -> feet -> centimeters
centimeters -> feet -> inches
centimeters -> feet -> yards

Answers

Answer:

yards feet centimeters

What is the result when you combine only the constants in the following expression?
3 a minus 6 b + 3 minus 7 a + 10

Answers

Answer:

6b-4a+13

Step-by-step explanation:

3a-6b+3-7a+10

3+10=13

3a-7a=-4a

6b-4a+13

Answer:

13

Step-by-step explanation:

I don’t get how they added to get the amount of money earned, I need help if you can explain how I can find the amount of money earned for 40 hours.

Answers

Answer:

its 34

Step-by-step explanation:

you just add

Answer:

330

Step-by-step explanation:

123.75 : 15= 8,25--> the money you earn in one hour.

8,25 x 10= 82,50--> the money you earn in 10 hours.

247,50 (30h) + 82,50 (10h)= 330 (40h)

:)

What is the product? (4x) (-3x^8)

Answers

Answer:

the product of (4x) (-3x^8)=-12x^9

Answer:

-12x^9

Step-by-step explanation:

multipy :)

Cast Iron Company, on each nondelinquent sale, receives revenues with a present value of $1,230 and incurs costs with a value of $1,065. Cast Iron has been asked to extend credit to a new customer. You can find little information on the firm, and you believe that the probability of payment is no better than 0.77. But if the payment is made, the probability that the customer will pay for the second order is 0.94. It costs $15.25 to determine whether a customer has been a prompt or slow payer in the past.
Calculate the minimum probability at which credit can be extended. (round answer 2 decimal places)

Answers

Answer:

[tex]P=0.866[/tex]

Step-by-step explanation:

From the question we are told that:

Present value of iron [tex]x_v=\$1230[/tex]

Present cost of iron [tex]x_c=\$1065[/tex]

Probability of payment [tex]P_p=0.77[/tex]

Probability that the customer will pay for the second order [tex]P_s=0.94[/tex]

Cost of knowing customer status [tex]x_k=\$15.25[/tex]

Generally the equation for Expected probability [tex]E_p[/tex] is mathematically given by

 [tex]E_p=(probability*(revenue-cost)-(1-probability)*present\ value\ of\ cost)[/tex]

 [tex]E_p=(P*(x_v-x_c)-(1-P)*X_c)[/tex]

  Where

  [tex]E_p=0[/tex]

  [tex]P=minimum\ probability\ at\ which\ credit\ can\ be\ extended[/tex]

Therefore

 [tex]0=(P*(1230-1065)-(1-P)*1065)[/tex]

 [tex]165P-1065+1065P=0[/tex]

 [tex]P=\frac{1065}{1230}[/tex]

 [tex]P=0.866[/tex]

Therefore the minimum probability at which credit can be extended is given as

 [tex]P=0.866[/tex]

 [tex]P=86.6\%[/tex]

NEED HELP WITH THIS please

Answers

Answer:

Step-by-step explanation:

this is A
……………………………..

Demetri wakes up at 9:15. It takes him
35 minutes to fold 4 loads of laundry,
35 minutes to bathe the dog, 45 minutes
to bake brownies, and 1 hour to mow the
lawn. After he finishes all of his chores,
he sits down to rest. What time does
Demetri rest?

Answers

Answer:

12:10

Step-by-step explanation:

We need to add up the times:

35 mins+ 35 mins + 45 mins+ 60 mins= 35+35+45+60= 175 mins

In hours, that would be 2 hrs, and 55 mins

So; 9:15 + 2 hrs and 55 mins= 12:10

Right Triangles

Solve the right triangle shown in the figure
∠C = 90°, BC = 7.50mi, AC = 11.43mi

a. AB = 19.5mi, ∠A = 31.2°, ∠B = 58.8°
b. AB = 16.mi, ∠A = 35.2°, ∠B = 54.8°
c. AB = 13.7mi, ∠A = 33.3°, ∠B = 56.7°
d. No triangle satisfies the given conditions.

Please select the best answer from the choices provided

Answers

Answer:

C. AB = 13.7mi, ∠A = 33.3°, ∠B = 56.7°

Step-by-step explanation:

I calculated it logically

can anyone solve this rq, it’s due tonight?

Answers

Answer:

The slope represents the change/rise is the yearly imcome based on age. The y-intercept is the amount that they make when they first get a job.

Step-by-step explanation:

The table below shows the values for the function
y = f(x).

Complete the table for the
function
y = f(1/5x).

Answers

Given:

The table of values of function [tex]y=f(x)[/tex] is given.

To find:

The table of values of function [tex]y=f(\dfrac{1}{5}x)[/tex].

Solution:

The horizontal stretch is defined as:

[tex]g(x)=f(ax), 0<a<1[/tex]

Here, f(x) is horizontally stretched by factor a to get g(x).

The given function is:

[tex]y=f(\dfrac{1}{5}x)[/tex]

It means the function [tex]y=f(x)[/tex] is horizontally stretched by factor [tex]\dfrac{1}{5}[/tex] to get [tex]y=f(\dfrac{1}{5}x)[/tex].

So, we need to multiply the given x-values by 5 to get the required table of values.

Therefore, the required table of values is:

  x         y

-20        7

 -5       -2

  0        3

 15       -4

30        5

Pls help!!
Jody has 15 pound bag of potatoes. She uses 3/4 of the bag to make potato salad. How many pounds of potatoes does Jody use for the potato salad?

Answers

Answer:

11.25

Step-by-step explanation:

15x3/4=45/4=11.25pounds

Please send me the graph of -x²-5x+6​

Answers

Answer:

-\left(x-1\right)\left(x+6\right)

Step-by-step explanation:

-\left(x^2+5x-6\right)


Question 40 of 43
Researchers conduct a study to evaluate the level of
pollution present in a river. They select several locations
along the river and then take a sample of water from each
location.
What is the population under study?

ILL GIVE BRANLIEST OR HOWEVER YOU SPELL IT

Answers

Answer:

c

Step-by-step explanation:

i did it

Answer:

The correct answer is C.

Step-by-step explanation:

I did the exam.

find f(3) for the polynomial function F(x)=x^3-9x^2+5x-2

Answers

Answer:

f(3) = -41

Step-by-step explanation:

f(x) = x³-9x²+5x-2

now,

f(3) = 3³-9×(3)²+5×3-2

= 27-9×9+5×3-2

= 27-81+15-2

= -41

7. A box contains 10 black, 12 white, and 18 red balls. One ball is drawn at
random and replaced. (a) Find the theoretical probability that the ball
drawn is black. (b) Balls are chosen and replaced 40 times. Look at the
table below, find the experimental probability that the ball drawn is black.
(c) Compare the experimental probability of the black ball drawn to its
theoretical probability.
Table:
Color. Times picked
black. 15
white. 12
red. 13

Answers

Answer:

1. 10/40 = 1/4

1b. 15/40 = 3/8

1c. 10/40 = 1/4 and 15/40 = 3/8

Step-by-step explanation:

1. So since there are 40 balls (18 + 12 + 10) and 10 of those balls are black the theoretical probability would just be 10 over 40, ([tex]\frac{10}{40}[/tex]).

1b. On the table there are 15 black balls so that would be, [tex]\frac{15}{40}[/tex].

1c. The theoretical probability is 1/4 and the experimental probability is 3/8.

pleaseeee helppppppp

Answers

Answer:

The answer is A [   5(a + 6)   ]

Step-by-step explanation:

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