Assume that the finishing times in a New York City 10-kilometer road race are normally distributed with a mean of 55 minutes and a standard deviation of 10 minutes. Let X be a randomly selected finishing time.

a. What percent of finish times was higher than 72 minutes? (Give your answers rounded to two decimal places)

b. What percent of finish times was between 52 and 70 minutes? (Give your answers rounded to two decimal places)

c. What is the 40th percentile finish time? (Round your answer to nearest tenth)

d. What is the 95th percentile finish time? (Round your answer to nearest tenth)

Answers

Answer 1

Using the normal distribution, it is found that:

a) 4.46% of finish times was higher than 72 minutes.

b) 55.11% of finish times was between 52 and 70 minutes.

c) The 40th percentile of finish times is 52.5 minutes.

d) The 95th percentile of finish times is 71.45 minutes.

In a normal distribution 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]

It 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, which is the percentile of X.

In this problem:

The mean is of 55 minutes, hence [tex]\mu = 55[/tex].The standard deviation is of 10 minutes, hence [tex]\sigma = 10[/tex]

Item a:

The proportion is 1 subtracted by the p-value of Z when X = 72, hence:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{72 - 55}{10}[/tex]

[tex]Z = 1.7[/tex]

[tex]Z = 1.7[/tex] has a p-value of 0.9554

1 - 0.9554 = 0.0446

0.0446 x 100% = 4.46%

4.46% of finish times was higher than 72 minutes.

Item b:

Th proportion is the p-value of Z when X = 70 subtracted by the p-value of Z when X = 52, hence:

X = 70:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{70 - 55}{10}[/tex]

[tex]Z = 1.5[/tex]

[tex]Z = 1.5[/tex] has a p-value of 0.9332.

X = 52:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{52 - 55}{10}[/tex]

[tex]Z = -0.3[/tex]

[tex]Z = -0.3[/tex] has a p-value of 0.3821.

0.9332 - 0.3821 = 0.5511

0.5511 x 100% = 55.11%

55.11% of finish times was between 52 and 70 minutes.

Item c:

The 40th percentile is X when Z has a p-value of 0.4, so X when Z = -0.253.

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]-0.253 = \frac{X - 55}{10}[/tex]

[tex]X - 55 = -0.253(10)[/tex]

[tex]X = 52.5[/tex]

The 40th percentile of finish times is 52.5 minutes.

Item d:

The 95th percentile is X when Z has a p-value of 0.95, so X when Z = 1.645.

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]1.645 = \frac{X - 55}{10}[/tex]

[tex]X - 55 = 1.645(10)[/tex]

[tex]X = 71.45[/tex]

The 95th percentile of finish times is 71.45 minutes.

A similar problem is given at https://brainly.com/question/24663213


Related Questions

The expression on the left side of an equation is shown below.
-4(x-2)+5x=0
If the equation has no solution, which expression can be written in the box on the other side of the equation?
2(x+4) - x
O x + 8
O 4(x + 2) - 5x
Ο Χ

Answers

Answer:

x + 8

Step-by-step explanation:

Expanding the equation

-4(x-2)+5x = -4(x-2)+5x

= -4x+8+5x

= -4x+5x + 8

= x+8

IMG World of Adventures sold 350 children's tickets last month . If this made up 12.5% of its yearly children's ticket sales, how many children's tickets did IMG World of Adventures sell all year? (WRITE ONLY THE NUMBER)

Answers

I'm sorry if I'm wrong

A farmer wants to increase the area of His rectangular pen but keep the pen a rectangular shape. He decides to a 5.7 yards of fencing
to the width of the pen but the length will remain 9.5 yards. The new area will be 77.9 square yards.
Which can be used to determine the original width of the pen?
5.7 (W+9.5) = 77.9
S95219
9.5 (W + 5.7) = 77.9

Answers

Using the equation for the area of a rectangle, the original width of the pen is determined by:

9.5 (W + 5.7) = 77.9

The area of a rectangle of length l and width w is given by:

[tex]A = lw[/tex]

In this problem:

Increases the width by 5.7 yards, hence [tex]w = w + 5.7[/tex], in which w is the original width.The length remains at 9.5 yards, hence [tex]l = 9.5[/tex].The area is of 77.9 square yards, hence [tex]A = 77.9[/tex]

Then:

[tex]A = lw[/tex]

[tex]9.5(w + 5.7) = 77.9[/tex]

For a similar problem, also involving the area of a rectangle, you can check https://brainly.com/question/10489198

Are the expressions 0.85b-0.2b and 0.65b equivalent?

Answers

Hello!

0.85b-0.2b

0.65b

0.65b=0.65b

So these expressions are equivalent.

Hope it helps!

~Just a determined gal

#CarryOnLearning

[tex]MysteriousNature[/tex]

Tamara bought a $22 mailbox using a 10% off coupon David bought an identical mailbox for $19.95 at a different store
Which statement is true?
Thank you

Answers

Answer:

I don't see any statements, but Tamara paid less. She paid 19.8 after the discount. David spent a little more at 19.95

The ratio of boys to girls in the class is 4 to 5. If there are 18 boys and girls in the
class, how many of each are there?

Answers

Answer:

8 boys and 10 girls

Step-by-step explanation:

If the ratio is 4:5,

4x2 + 5x2 equal 8+10 =

18.

4:5=8:10

Answer:

8 boys

10 girls

Step-by-step explanation:

4:5

8:10

8+10=18

Use Pythagoras Theorem to determine which of the following shapes are rectangles. please awnser ​

Answers

Answer:

(a) - no, (b) - yes

Step-by-step explanation:

Use equation and compare results:

d² = a² + b²

(a)

10.15² = 8.1² + 6.3²103.0 ≠ 105.3, no

(b)

15.31² = 14.4² + 5.2²234.4 = 234.4, yes

#a

[tex]\\ \sf\longmapsto H^2=P^2+B^2[/tex]

[tex]\\ \sf\longmapsto (10.15)^2=(8.1)^2+(6.3)^2[/tex]

[tex]\\ \sf\longmapsto 103=65.61+39.69[/tex]

[tex]\\ \sf\longmapsto 103\neq 105.3[/tex]

No

#b

[tex]\\ \sf\longmapsto H^2=P^2+B^2[/tex]

[tex]\\ \sf\longmapsto (15.31)^2=(14.4)^2+(5.2)^2[/tex]

[tex]\\ \sf\longmapsto 234.4=207.3+27.1[/tex]

[tex]\\ \sf\longmapsto 234.4\neq 234.4[/tex]

Yes

6. Jasper pays $42.8 for his cell phone. Marco pays $38.15 for his cell phone plan.
How much more does Jasper pay? Do not use a $ sign. Just type in the numbers.

Answers

Answer: 4.65

Step-by-step explanation: 42.80 - 38.15 = 4.65

Derrick earns $14 per hour working at Pizza Palace. What will Derrick's new hourly rate be after a 4.5% raise.

Answers

14x4,5÷100=0,63

14+0,63=14,63

2x5 what would 2x5=?

Answers

Answer:

10

Step-by-step explanation:

Answer:

10 would be the answer.

Step-by-step explanation:

2+2+2+2+2 Hope this helps!

What is 10 plus 5 to the 3 power minus 1? Order of operation

Answers

3374 is the answer.


Hope this helped!! :)

Step-by-step explanation:

(10+5)³-1 = 3375-1 = 3374.

a pacific seahorse eats about 56 shrimp per week how much does it eat per day

Answers

56 divided by 7
Equals 8

8 is the answer

see image above ^^^^​

Answers

Answer: A reflection, and then a translation.

SOLVE THE CORRECT ANSWER!

1.234.45 added to the difference of 89 and 23.765

2. increase 234.57 by the difference of 5.23 and 2.678

3.subtract 68.501 from the sum of 21.54
and 80.27

please paki answer po ng maayos need ko po ng solution​

Answers

Step-by-step explanation:

1.

123445+(89-23765)=99769

2.

234.57+(5.23-2.678)=237.122

3

(21.54+ 80.27)-68.501=33.309

Helen counted six dollars and four cents in her purse. She recorded this amount in decimal form as $6.40. Did she record it correctly? If she made a mistake, what is the correct way
to record this amount of money as a decimal?

Pls answer will give brainiest

Answers

Answer:

6 dollars and 4 cents

Step-by-step explanation:

15.
The number of calories in a 100-g serving of fruit varies by the type of fruit. A snack consisting of
on serving each of peach, apple, and banana contains 124 calories. A snack consisting of two
servings of peach and one serving of banana contains 160 calories. A snack consisting of one
serving of peach, 2 servings of apple, and two servings of banana contains 188 calories. How
many calories are in a 100-g serving of each type of fruit?

Answers

Answer:

A=24, B=40, P=60

Step-by-step explanation:

given:

P+A+B=124

2P+B=160

P+2A+2B=188

___________

P=188-2A-2B

P=124-A-B

188-2A-2B=124-A-B

188-A-B=124

188=124+A+B

A+B=64

___

P+A+B=124

P=60

___

2P+B=160

120+B=160

B=40

___

A+B=64

A=24

___

If we substitute each variable in the three given equations for these values, the equations hold true. Therefore, these are the correct values.

You may use a calculator for this item,
Zach, Kolby, and Peyton are investing a total of $360,000 to open a cottee shop Their investments are in the radio
1:2:0.5, respectively
How much has Zach invested, in dollars?
Enter your answer in the space provided

Answers

Based on the investment ratio and the amount invested, the amount that Zach invested is $102,857.14.

First thing to do is to add up the numbers in the ratio:

= 1 + 2 + 0.5

= 3.5

The amount that Zach invested is:

= Zach's ration/ Sum of ratio x Amount invested

= 1 / 3.5 x 360,000

= $102,857.14

In conclusion, Zach invested $102,857.14.

Find out more at https://brainly.com/question/17061956.

consider the system of equations. which shows an equivalent system of equations?
see attatched

Answers

Answer:

A.

Step-by-step explanation:

All choices show the first original equation.

Each choice shows a different second equation.

Take the second original equation:

6x + 5y = 30

Multiply both sides by -5.

-30x - 25y = -150

Answer: A.

Will give brainliest to whoever helps pls

Answers

Answer:

for me the picture is blurry sorry

Step-by-step explanation:

Answer:

-23

Step-by-step explanation:

Solve the equation 3x - 2(x + 1) = 2x - 7

Answers

Answer:

X=5

Step-by-step explanation:

Collect like terms then move the terms. Then collect liked terms. Calculate and Chang signs

Answer:

X = 5

Remember, x has a hidden one behind it, so it would be 1x

3x - 2(x + 1) = 2x - 7

Use the distributive property to multiply −2 by x+1.

3x−2x−2=2x−7

Combine 3x and −2x to get x

x−2=2x−7

Subtract 2x from both sides

x−2−2x=−7

Combine x and −2x to get −x

−x−2=−7

Add 2 to both sides

−x=−7+2

Add −7 and 2 to get −5

−x=−5

multiply both sides by -1

x=5

how do I make this as simplest form
qns: 5 2/3 + 3 1/10
pls answer
the prod. is 8 23/30 ​

Answers

Answer:

That is the final product

Step-by-step explanation:

According to all sites I used, they all said that was in the simplest form and cannot be simplified lower than that.

HELPPP LAST ATTEMPT!!

Answers

Answer:

Here’s something I wrote that can help you. I don’t really wanna do transformations but this should help you get the answer in a snap.

ONLY FOR REFLECTIONS

Over the x-axis:  (x, y) — > (x, –y)

Over the y-axis:  (x, y) — > (–x, y)

Over the line y = x:  (x, y) — > (y, x)

Through the origin:  (x, y) — > (–x, –y)

So for example E is (6,-1)

Over the y axis so following the coordinate plane rules, (6,-1) — > (-6, -1)

(-6, -1) over x axis which is following the rules

(-6, -1) — > (-6, 1)

Final answer (-6,1)

Answer:

(-6, 1)

Step-by-step explanation:

If you reflect over y-axis and x-axis it is just the opposite of each number.

5. Mohan and Sohan have the same storybook. Mohan has read 2/5 of the book and Sohan has read 2/7 of the book. Who has read more pages? 6. Sonali and Priya are classmates Sonali completed her homework in a of an hour and Priya in of an hour 3/4 . Who was faster?

Answers

#5

Mohan read =2/5Sohan read=2/7

Compare

[tex]\\ \sf\longmapsto \dfrac{2}{5}>\dfrac{2}{7}[/tex]

Mohan read more pages.

#6

Sonali completed in=1/2Priya completed in=3/4

[tex]\\ \sf\longmapsto \dfrac{1}{2}=\dfrac{2}{4}[/tex]

Compare

[tex]\\ \sf\longmapsto \dfrac{2}{4}<\dfrac{3}{4}[/tex]

Sonali was faster

Roger’s office building has a $320,000 value, a 2 rating, and a B building classification. The contents in the building are valued at $105,000. Calculate his total annual premium.

Answers

Answer:

2,230

Step-by-step explanation:

In year one the population of rabbits is 100. In year three the population is 300. Assuming the population is to go unchecked and is linear what will be the population in year 10? Construct a formula for this.

Answers

Answer:

the rabbits ran away

Step-by-step explanation:

now its 300 rabbits

a. Does it take more cups or gallons to measure the amount of water in a large
a
pot? Explain.

Answers

If the amount of water is more than 1 gallon it would take more cups to measure the amount of water

Which relation is not a function?​

Answers

D because the same root can’t make two different answers

The number of eggs Mia can sell varies directly with the number of chickens she owns. The more hens she owns, the more
eggs she can sell. If she has 38 eggs each week when she owns 6 chickens, then how many eggs will she get if she has 15
chickens?

Answers

answer:
if she has 6 chickens and she sells 38 per week. you need to do (38 divided by 6) which would equal to 6.3 recurring (6.33333’) so now you’ve found out that one chicken is equivalent to 6.3333’ eggs you do (6.3333333x15) which is equal to 95

hope it helps

If there are 15 chickens. Then the number of eggs will be 95.

What are ratio and proportion?

A ratio is a group of sequentially ordered numbers a and b expressed as a/b, where b is never equal to zero. When two objects are equal, a statement is said to be proportional.

The number of hens Mia has directly affected how many eggs she can sell. She can sell more eggs if she has more chickens. If she has 6 hens and produces 38 eggs every week.

Let the number of eggs be x. Then the equation is written as,

x / 15 = 38 / 6

x = 95

If there are 15 chickens. Then the number of eggs will be 95.

More about the ratio and the proportion link is given below.

https://brainly.com/question/14335762

#SPJ2

Given (x – 7)2 = 36, select the values of x.

x = 13

x = 1

x = –29

x = 42

Answers

Answer:

x = 13 and x = 1

Step-by-step explanation:

(x-7)² = 36

simplify left side of equation

x² - 14x + 49 = 36

Our object now is to get every thing on the left side of the equal sign so we can factor. To do this, we subtract 36 from both sides

x² - 14x + 13 = 0

we then factor the left side of the equation

( x - 1 ) ( x - 13 ) = 0

we then set factors equal to 0 and solve both factors for x

x - 1 = 0

add 1 to both sides

x = 1

x - 13 = 0

add 13 to both sides

x = 13

The values of x are x = 13 and x = 1

I will give Brainliesttttt :D!

A car's gas mileage is the distance it can go using 1 gallon of gas (measured in miles per gallon).

Based on the graph, what is this car's gas mileage? Explain.​

Answers

Answer:

20 mpg

Step-by-step explanation:

Answer:

The car is traveling 20 miles per gallon.

Step-by-step explanation:

There are two ways you can solve this.

1) Since this is a graph of the car's gas mileage, all you have to do is look to find the miles for one gallon, which is plotted in this case. As you can see, for one, it is plotted halfway between 0 and 40, so that means the mile number would be 20. Looking at this, the car travels 20 miles per gallon.

2) You can also look at the point at the top that is clearly defined, and the point is (12, 240), 12 gallons used for 240 miles. To get the exact number of miles for one mile, you would divide 12 and 240 both by 12, which results in (1, 20). Since it is miles per gallon, the car gas mileage is 20 miles per gallon.

Hope this helped and have a great day!

Other Questions
what is a phosphorelated nucleoside? Please help me with Spanish work please!!! the x-coordinate is zero and the y-coordinate is positive choose the location What does sentir mean in English? to feel to kill to order to drink. Pleeeeasee someone whos good at chemistry?! 10 grade ASAPIll give points, just help please Can someone explain or help me with this? what is the perimeter of khgj? a block weighing (Fg) 500 N is resting on a steel table ( us=0.74) the minimum force start this block moving is? Please , I know a little by of English , can you help me whit this ? :,) A projectile is launched with a horizontal velocity of 20 m/s and an initial vertical velocity of 20 m/s. What is the projectile's acceleration in the Horizontal direction? Verticle direction? What is the molecule that leaves the calvin cycle to be converted into glucose?. Is the circled karyotype a male or female?femalemale 1. Habla cinco personas sentadas a la mesa, pero an faltaba Tomas. 2. Antes no sabia nada acerca del bisbol, pero luego de leer la informace en internet, me considero un experto, 3. El almirante dio la orden para que la flota zarpara a primera luz. 4. Maria haba perdido la esperanza de encontrar el celular y decidi comprar o S. Mauricio nos cont que visit el Gran Can en Arizona durante el verano. 6. Mi primito se escondi entre los estantes de la biblioteca. 8. Clasica Which country holds the leading position of mining in Europe?Poland Bulgaria Finland Sweden Which graph represents a proportional relationship? what happened to nellie on little house on the prairie What is ONE way in which geologists may utilize GPS and satellite mapping? nev is giving a speech on musical composition to a retirement community for its residents. he tells the audience about his degree in music and the award he won for a song he composed. nev is enhancing his credibility as a speaker by someone please help meeeee! I don't know what the solution is! Mary places a 15-foot ladder against her house. The base of the ladder is 3 feet from her house How high up to the nearest tenth of a foot, the ladder reach on Mary's house?taking math test plz help