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

Mr Harrison is 9 months old. How old is Mr Harrison daughter in days​

Answers

Answer:

273.75 days

Step-by-step explanation:

Find the unknown angle in the figure

Answers

Answer:

Angle 145 degrees

Step-by-step explanation:

Hope it can help you lovelots

Write a ratio for 2 batches of this recipe.

Answers

1/2 1/2 of what recipe tho??

Two sides of a triangle measure 27 inches and 32 inches.
Which could represent the length of the third side?


Answer options:

5 in


59 in


7 in


62 in

Answers

Answer:

62 in

Step-by-step explanation:

the Hypotenuse of a triangle is always longer than the two other sides, 27 + 32 is larger than all but one of the options, 62. Making 62 the answer by process of elimination.

Write the expression that represents the sum of
double a number and triple a number.

Answers

Answer: let x = the "number"

2x + 3x is the expression

Step-by-step explanation:

Ana is a dedicated Skee Ball player (see
photo) who always rolls for the 50-point slot. The
probability distribution of Ana’s score X on a single
roll of the ball is shown below. You can check that
Mx = 23.8 and og
12.63.

Find and interpret mean

Find and interpret standard deviation

Answers

Answer:

i dont know 69 420?

Step-by-step explanation:

Which symbol correctly compares the numbers?
-0.64 0-0.5
O>
O <
O I don't know.

Answers

Answer:

<

Step-by-step explanation:

-0.5 is greater than -0.64

We need to find the symbol -0.64 ,0-0.5. -0.64<0-0.5.

What is Number system?

A number system is defined as a system of writing to express numbers.

We need to find which symbol is used between Minus zero point six four and minus zero point five.

-0.64 and -0.5

As we know that the integers are number with positive, Negative and zero.

-0.64<-0.5

On the number line the integer -0.64 lies on left of -0.5.

So -0.64 is less than -0.5.

Hence -0.64 is less than -0.5.

To learn more on Number system click:

https://brainly.com/question/22046046

#SPJ5

What's the kinetic energy of an object that has a mass of 12 kilograms and moves with a velocity of 10 m/s?

Answers

Answer:

Step-by-step explanation:

Assuming it has no spin

KE = ½mv²

KE = ½(12)10²

KE = 600 J

A rectangular poster has a area of 504 centimeters. The width of the poster is 14 centimeters. How long is the poster?

Answers

Answer:

36 cm

Step-by-step explanation:

504/14=36

Gven: f(x) = 4x +1 and (x)= x^2 + 1.

find (fog)(x)​

Answers

Answer:

Step-by-step explanation:

27836?+_68_729+_8978

pls help me find the missing angle​

Answers

Answer:

b=114

c=43................

Please take a look at the picture

Answers

Answer:

B) -g/-h

Step-by-step explanation:

-g/-h=g/h

Rewrite the fraction.

-(-g/h) = g/h

Hope this helps :)

Hello Please help me.

Answers

Answer:

Step-by-step explanation:

1) D

2) B

3) no solution

y ≤ 0.5x - 4 is area C including the red line

y ≥ 0.5x + 5 is area A including the blue line

п
What is the end behavior of the polynomial function?
1
8
B
4
2
6
2
2
8
B
X
-4
6
o As X->-co, then Y---
As X-→-00, then y0
As X-0, then y →-00
ne X -> then V -> 0

Answers

Answer:

The end behavior of a polynomial function is the behavior of the graph of f(x) as x approaches positive infinity or negative infinity

Step-by-step explanation:

hope this help

dont know if this is correct

The end behavior of the polynomial function is as x -> ∞, y -> -∞

How to determine the end behavior?

From the graph of the polynomial, we have the following highlight:

As x approached infinityThe function approaches negative infinity

The above highlights mean that:

As x -> ∞, y -> -∞

Hence, the end behavior of the polynomial function is as x -> ∞, y -> -∞

Read more about end behavior at:

https://brainly.com/question/1365136

#SPJ5

For homework, Tina is asked to write down the opposite value for each number listed. Which comparison did Tina write incorrectly?

Answers

Answer:

x

Step-by-step explanation:

It still would be a negative.

The comparison that Tina wrote incorrectly is X. Then the correct option is B.

What is Algebra?

Algebra is the study of abstract symbols, while logic is the manipulation of all those ideas.

The acronym PEMDAS stands for Parenthesis, Exponent, Multiplication, Division, Addition, and Subtraction. This approach is used to answer the problem correctly and completely.

The table is given below.

Comparison         Number          Opposite value

       W                      -3                       3

       X                      -(-9)                    9

       Y                        0                      0

       Z                        4                    - 4

The number -(-9) is also written as 9 and the opposite number of 9 is negative 9. Then the comparison that Tina wrote incorrectly is X. Then the correct option is B.

More about the Algebra link is given below.

https://brainly.com/question/953809

#SPJ2

One snowy day, the snow was falling at a rate of 3 inches per hour.
If it kept snowing at the same rate, now many inches would
accumulate in 24 hours
artice
соо

Answers

Answer:

72 inches

Step-by-step explanation:

You would multiply the 3 inches per hour times the 24 hours to get 72 inches of snow.

Answer:

72 Inches

Step-by-step explanation:

24x3=72

23 x 5 + 6 x 50 -7 = ?

Answers

Answer:   Your anwser would be 408 please mark brainliest thank you

Step-by-step explanation:

Answer:408

Step-by-step explanation:

To find the answer, we can use the order of operations ( PEMDAS)

23*5=115

6*50=300

so simplified

115+300-7

add

415-7

subtract

408

so 23*5+6*50-7=408

A line that passes through the points (12,12) and (20,6)

Answers

Answer:

8,48 I think

Step-by-step explanation:

I subtracted them from each other

The required equation of the line is given as y = -6x / 8 + 21.

Given that,
A line that passes through points (12,12) and (20,6)

What is the slope of the line?

The slope of the line is a tangent angle made by line with horizontal. i.e. m = tanx where x in degrees.

here,
Standard equation of the line,

y -y₁ =(y₂ - y₁) /  (x₂ - x₁) (x - x₁)

Substitute the point in the above equation,
y - 12 = (6-12)/(20 - 12)[x - 12]
y = -6/8[x - 12] + 12
y = -6x/8 +9 + 12
y = -6x / 8 + 21

Thus, the required equation of the line is given as y = -6x / 8 + 21.

Learn more about slopes here:
https://brainly.com/question/3605446

#SPJ2

Please take a look at the picture

Answers

Answer: C

Step-by-step explanation:

How many ⅖ are in 1½

Answers

Answer:

3 (remainder 3)

Step-by-step explanation:

Find the surface area of this cuboid

Answers

Answer:

62

Step-by-step explanation:

SA=2(5x2)+2(5x3)+2(3x2)

SA=20+30+12

SA=62

The scatter plot shows a regression line of advertising dollars spent and sales. If the company were to spend $6,500 on advertising, what would be the predicted sales?
A) $110,000
B) $114,000
C) $118,000
D) $122,000

HELPPP PLEASE IM GIVING OUT BRAINLIEST

Answers

Answer:

C

Step-by-step explanation:

A jet is flying in a direction N 70° E with a speed of 600 mi/h. Find the north and east components of the velocity. Round to two decimal places.

Answers

Using vector concepts, it is found that the components of the velocity are given as follows:

North: 205.21 mi/h.East: 563.82 mi/h.

How can a vector be represented in i and j notation?

Given a magnitude M and angle [tex]\theta[/tex], the a vector V can be represented as follows:

[tex]V = M\sin{\theta}i + M\cos{\theta}j[/tex]

In which:

i is the horizontal(east/west) component.j is the vertical(north/south) component.

In this problem, we have that the magnitude and the angle are given as follows:

[tex]M = 600, \theta = 70^{\circ}[/tex]

Hence the north component is:

[tex]600\cos{70^{\circ}} = 205.21[/tex]

And the east component is:

[tex]600\sin{70^{\circ}} = 563.82[/tex]

More can be learned about vectors at brainly.com/question/24606590

#SPJ1

Please take a look at the picture

Answers

Answer:

I think it'

is A and B

Step-by-step explanation:

hope hwlps

what is this simplified as a fraction

Answers

Step-by-step explanation:

35/48

this cannot be simplified any further

so 13+139+123+129 so WHAT does this =

Answers

Answer:

404

Step-by-step explanation:

you just add numbers you know first

Help pls asap!!! Make sure to answer all of them!

Answers

Answer:-4

-3

-2

Step-by-step explanation:

thx

A 52-centimeter-long board is cut into 3 pieces. The longest piece is twice as long as the shortest piece. The other piece is 4 cm longer that the shortest piece. How long is each piece?

Answers

Answer:

4c 6th fastest 9.I gghiii

what is one third the product of 2 numbers a and b.

Answers

Answer:

1/3 (a+b)

Step-by-step explanation:

The required solution is 1/3ab.

It is required to find the solution.

What is arithmetic?

Arithmetic is the branch of mathematics that deals with the study of numbers using various operations on them. Basic operations of math are addition, subtraction, multiplication and division. These operations are denoted by the given symbols.

Given:

Let the 2 numbers be a and b.

According to given question we have,

Product =a× b=ab

1/3 of product =1/3ab

Therefore, the required solution is 1/3ab.

Learn more details about arithmetic here:

https://brainly.com/question/11559160

#SPJ2

the length of a rectangle in (3+√7) and it's with is (1+2√7). what is the area of the rectangle? what is the perimeter of the rectangle​

Answers

Answer:

Area: (3+√7) x (1+2√7) = 17+7√7 = 35.52

Perimeter: 2(3+√7) + 2(1+2√7) = 8+6√7 = 23.87

Other Questions
Write an equation in slope intercept form for the graph of the line. Wagner Resources was unable to meet its financial obligations. Its creditors forced it into using legal proceedings to restructure itself so that it could continue as a viable business. The process this company underwent is known as a: I need help surface area Calculate the acceleration of a bottle rocket that is traveling at a speed of 74 m/s, and then descends at a speed of 89 m/s. It takes the rocket 5 seconds to change its speed. a) 1 m/s/sb) 2 m/s/sc) 3 m/s/sd) 4 m/s/s A bidirectional relationship exists between personality, behavior, and the environment. This relationship is called __________ . Draw a line representing the "rise" and a line representing the "run" of the line. Statethe slope of the line in simplest form. entperise opportunities 3/10y - 2/5 i need to find the coefficient and i dont know how Are (1,1.5) and (12,4) solutions to the equation y=1/4x+5/4 how long does it take for your pores to close after a shower why different types of engines used gas turbine give reasons need helps i will give brainliest Can this picture be presented as a bar graph? why or why not? The social hierarchy of medieval Europe was... Group of answer choicesthe monarchy, the knights, the lords, the merchants and farmers, the peasants.the monarchy, the lords, the vassals, the merchants, the farmers, the peasants.the monarchy, the lords, the vassals, the knights, the merchants, the peasants.the king, the lords, the knights, the merchants and farmers, the peasants. A student tested a variety of interacting forces to determine how they would result in motion of an object. If the student used the forces as shown in the lettered choices above, predict which results would occur. Select ALL that apply.A)The variable shown by letter B would result in a movement of the object to the left.B)The variable shown by letter B would result in a movement of the object to the right.C)The variable shown by letter A would result in a movement of the object to the right.D)The variable shown by letter C would result in a movement of the object to the right.E)The variable shown by letter D would result in a movement of the object Why nutrition matter for the early years? In which layer of the atmosphere is the ozone layer located? What feature of a planet's orbit does Kelper's first law of motion describe?A. the time required for each orbitB. the shapeC. the distance from the aphelion to the perihelionD. the distance to the sun What is the possible resultant of a 2-unit vector and 4-unit vector? Select the correct answer.The difference of half a number and its reciprocal is represented by this expression.Which expression also represents the difference?