High school students from track teams in the state participated in a training program to improve running times. Before the training, the mean running time for the students to run a mile was 402 seconds with standard deviation 40 seconds. After completing the program, the mean running time for the students to run a mile was 368 seconds with standard deviation 30 seconds. Let X represent the running time of a randomly selected student before training, and let Y represent the running time of the same student after training. Which of the following is true about the distribution of X-Y?a. The variables X and Y are independent, therefore, the meanis 34 seconds and the standard deviation is 10 seconds.b. The v ales X and Y are independent therefore, the meanis 34 seconds and the standard deviation is 50 secondsc. The variables X and Y are not independent, therefore, the standard deviation is 50 seconds and the mean cannot be determined with the information given.d. The variables and are not independent, therefore, the meanis 3 seconds and the standard deviation cannot be determined with the information givene. The variables X and Y We not independent, therefore, neither the mean nor the standard deviation can be determined with the informantion given.

Answers

Answer 1

Answer:

b. The values X and Y are independent therefore, the mean is 34 seconds and the standard deviation is 50 seconds

Step-by-step explanation:

Subtraction between normal variables:

When two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.

Before the training, the mean running time for the students to run a mile was 402 seconds with standard deviation 40 seconds.

This means that [tex]\mu_X = 402, \sigma_X = 40[/tex]

After completing the program, the mean running time for the students to run a mile was 368 seconds with standard deviation 30 seconds.

This means that [tex]\mu_Y = 368, \sigma_Y = 30[/tex]

Which of the following is true about the distribution of X-Y?

They are independent, so:

[tex]\mu = \mu_X - \mu_Y = 402 - 368 = 34[/tex]

[tex]\sigma = \sqrt{\sigma_X^2+\sigma_Y^2} = \sqrt{40^2+30^2} = 50[/tex]

This means that the correct answer is given by option b.

Answer 2

The values X and Y are independent therefore, the mean is 34 seconds and the standard deviation is 50 seconds.

What is the subtraction between normal variables?

The two normal variables are subtracted, the mean is the difference of the means, while the standard deviation is the square root of the sum of the variances.

Before the training, the mean running mean  time for the students to runing a mile was 402 seconds with standard deviation 40 seconds.

That is the [tex]\mu_x=402 , \sigma_x=40[/tex]

That is the after completing the program, the mean running time for the students to run a mile was 368 seconds with standard deviation 30 seconds.

That is [tex]\mu_y=368,\sigma_y=30[/tex]

which of the following is true about the distribution of X-Y?

They are independent

Therefore we get,

[tex]\mu=\mu_x-\mu_y=402-368=34[/tex]

[tex]\sigma=\sqrt{\sigma_x^2-\sigma_y^2}\\\sigma=\sqrt{40^2-30^2}\\\sigma =50[/tex]

Therefore the option b is correct.

To learn more about the distribution visit:

https://brainly.com/question/24756209

This means that the correct answer is given by option b.


Related Questions

The following sample was collected during registration at a large middle school. At the 0.05 level of significance, can it be concluded that level of math is dependent on grade level?
Honors Math Regular Math General Math
6th Grade 34 45 15
7th Grade 37 49 13
8th Grade 29 45 17
Hypotheses:
sub(H,0): Level of math is independent of/dependent on grade level.
sub(H,1): Level of math is independent of/dependent on grade level.
Enter the expected matrix - round to 4 decimal places.
Honors Math Regular Math General Math
6th Grade
7th Grade
8th Grade
After running an independence test, can it be concluded that level of math is dependent on grade level?
Yes/No

Answers

Answer:

use Ma.thway it helps

Step-by-step explanation:

which of the statements below best describes the transformation of the graph of

f
(
9
x
)
?

Answers

Answer:

The transformation of the graphs is that of an expansive one as can be depicted by a value being multiplied onto the graph. This refers to an increase in the output value by the factor essentially spreading the graph out abroad.

Find the slope on the line?

Answers

Answer:

slope=0

Step-by-step explanation:

Hi there!

We're given a graph with a line and two marked points on the graph: (-1,3) and (3,3)

the formula given for slope calculated from two points is (y2-y1)/(x2-x1), where (x1,y1) and (x2,y2) are points

we have our two points: (-1,3) and (3,3) and we can label them:

x1=-1

y1=3

x2=3

y2=3

now substitute into the formula

note: Remember the formula shows SUBTRACTION, even though we have NEGATIVE numbers. When we simplify, we'll add the numbers.

slope=(3-3)/(3--1)

simplify

slope=0/4

divide

slope=0

Hope this helps!

what is the mean absolute deviation for 9, 7, 6, 8, 7, and 5? (2 points) a 1 b 2 c 6 d 7

Answers

Answer: a. 1

Step-by-step explanation:

Given data: 9, 7, 6, 8, 7, and 5.

Mean absolute deviation: [tex]MAD=\dfrac1n\sum^n_{i=1}|x_i-m|[/tex], where m = mean

mean (m) = [tex]\frac{\text{Sum of values}}{\text{Number of values}}[/tex]

[tex]=\frac{42}{6}\\\\=7[/tex]

Now, [tex]MAD=\dfrac{|9-7|+|7-7|+|6-7|+|8-7|+|7-7|+|5-7|}{6}[/tex]

[tex]MAD=\dfrac{2+0+1+1+0+2}{6}[/tex]

[tex]MAD=\dfrac{6}{6}[/tex]

[tex]MAD=1[/tex]

Hence, the mean absolute deviation=1

Thus correct option is a. 1

Can someone help me answering this question

Answers

Answer: Choice D)

Determine the percentage of values occurring above and below that value

==========================================================

Explanation:

Let's go through the answer choices

A) If we add up all the scores and divide by n, which is the number of scores, then we get the sample mean xbar. We can refer to this as simply the mean. This won't get us the percentile, so we can rule out choice A.B) Subtracting the max and min gets us the range. Range = max - min. We can rule out choice B. C) We can rule out choice C. The steps described here determine the mean absolute deviation (MAD) which is similar in nature to the standard deviation. It tells us how spread out the data set is, so it's somewhat related to the range as well. Unfortunately, we can't figure anything about percentiles with this.D) This must be the answer as there isn't anything left. Turns out this set of steps is the correct method to find the percentile. Technically all you need to do is the "below" portion and ignore the "above" portion of the statement. If we say "the 25th percentile is K", then that is another way of saying "25% of the data is below K".

Answer:

D

Step-by-step explanation:

What’s the answer and how do you figure these out?

Answers

you need to find the value of x that will make 4x = 2x (or in mathematical terms parallel. therefore the answer would be 0 since there is no other possible answer. hope this helps <3 make sure you eat today !

Help pleaseeeee thanks

Answers

Answer:

We know that 3 l 3 = 3.3, so the values of the stem and leaf plot would be;

4 l 8, 9

5 l 1, 6, 8, 8, 9

6 l 8, 9, 9, 9, 9

7 l 0, 2, 2, 2, 5, 5

8 l 0, 9

Hope this helps!

On average, there are 177,000 cars on the road every hour in Los Angeles. 1 point
In March 2020, the coronavirus shutdown, resulted in Los Angeles having
80% fewer cars on the road. How many cars were on the road in March
2020 every hour in Los Angeles, after the 80% reduction?

Answers

Answer:

Number of cars on road in 2020 = 35,400 car

Step-by-step explanation:

Given;

Number of cars on road = 177,000

Decrease in cars on road in 2020 = 80%

Find:

Number of cars on road in 2020

Computation:

Number of cars on road in 2020 = Number of cars on road[1 - Decrease in cars on road in 2020]

Number of cars on road in 2020 = 177,000[1-80%]

Number of cars on road in 2020 = 177,000[1-0.80]

Number of cars on road in 2020 = 177,000[0.20]

Number of cars on road in 2020 = 35,400 car

What is the solution to this system of equations?
3x+2y=−10
y=−x−4
Possible Answers
-2, -2 -2, 2 -18, 14 no solution

Answers

(-2,-2), x= -2, y= -2

What’s the answer to this one?

Answers

Sum of the interior angles of any triangle equal 180 degrees , Thus :

A + B + C = 180

48 + B + 67 = 180

B + 115 = 180

B = 180 - 115

B = 65 degrees

Answer:

B = 65°

Step-by-step explanation:

Area of triangle,

→ 180° = A + B + C

→ 180° = 48° + B + 67°

→ 180° = 115° + B

→ B = 180° - 115°

→ B = 65°

If there are 82 students and they read 1000 books what is the average number of books the students read round it to the nearest whole number

Answers

Answer:

12 books read per student

Step-by-step explanation:

1000 divided by 82 is close to 12

Answer:

12 books

Step-by-step explanation:

Since there are 82 students who in total read 1000 books, we need to find how many books each student read. To do that; Divide the number of books read by the number of students who read those books. Then round your answer to the nearest whole number as an estimate. In otherwords, in "tenths place".

Step 1: Divide 1000 by 82

[tex]1000\div 82\\\\= \frac{1000}{82} \\\\= 12.1951219512[/tex]

Now to round up. To round a number to the nearest whole number, you have to look at the first digit after the decimal point. If this digit is less than 5 (1, 2, 3, 4) we don't have to do anything, but if the digit is 5 or greater (5, 6, 7, 8, 9) we must round up. Since the digit after our result is less than 5, we do nothing.

Step 2: Round [tex]12.1951219512[/tex] in the nearest whole number

[tex]12.1951219512 \\= 12[/tex]

Therefore, the average number of books the student read rounded to the nearest whole number is 12 books.

Determine whether the following system is consistent or inconsistent and if it is independent or dependent.

Y=2x-3 and 2x-2y=2​

Answers

9514 1404 393

Answer:

  consistent, independent

Step-by-step explanation:

Systems of equations are most easily classified these ways if the equations are in the same form. If we solve the second equation for y, we have ...

  y = x - 1

The x-coefficients of this and the first equation are different, so the system is consistent and independent.

__

A system is independent if the equations describe different lines.

A system is inconsistent if the equations describe parallel lines.

Here, the different lines are not parallel, so the system is independent and consistent.

Tom is throwing darts at a target. In his last 30 throws, Tom has hit the target 20 times. You want to know the estimated probability that exactly one out of the next three throws does not hit the target.

Categorize the simulations as correct or incorrect simulations of Tom’s scenario.

Roll a six-sided die three times. The
numbers 1 to 4 represent hits, and
5 and 6 represent misses.
Spin a spinner with three equal sections
three times. On the spinner, one section
represents a miss and two sections
represent hits.
Generate a set of three numbers using
a number generator with numbers
between 0 and 9. The numbers 0 to 7
represent hits, and 8 and 9 represent
misses.
Generate a set of three numbers using
a number generator with numbers
between 0 and 8. The numbers 0 to 5
represent hits, and 6 to 8 represent
misses.
Spin a spinner with six equal sections
three times. On the spinner, four
sections represent hits and two
sections represent misses.

Answers

Answer:

no

Step-by-step explanation:

N (4,-2)
Given the point A(-2, 3) and B(4,8), determine the coordinates of point P on directed line segment AB that
partitions AB in the ratio 1/5.

Answers

Yes 4/16 is the answer mhmmmmm

20% of the patron's order the chef's special. The probability that 2 out of the next ten customers will order the chef's special is

Answers

Answer:

[tex]P(x =2) = 0.3020[/tex]

Step-by-step explanation:

Given

[tex]p =20\% = 0.20[/tex]

[tex]n = 10[/tex]

Required

[tex]P(x = 2)[/tex]

This question is an illustration of binomial distribution where:

[tex]P(X = x) = ^nC_x * p^x * (1 - p)^{n-x[/tex]

So, we have:

[tex]P(x =2) = ^{10}C_2 * 0.20^2 * (1 - 0.20)^{10-2}[/tex]

[tex]P(x =2) = ^{10}C_2 * 0.20^2 * 0.80^8[/tex]

This gives

[tex]P(x =2) = \frac{10!}{(10 - 2)!2!} * 0.20^2 * 0.80^8[/tex]

[tex]P(x =2) = \frac{10!}{8!2!} * 0.20^2 * 0.80^8[/tex]

Expand

[tex]P(x =2) = \frac{10*9*8!}{8!2*1} * 0.20^2 * 0.80^8[/tex]

[tex]P(x =2) = \frac{10*9}{2} * 0.20^2 * 0.80^8[/tex]

[tex]P(x =2) = 45 * 0.20^2 * 0.80^8[/tex]

[tex]P(x =2) = 0.3020[/tex]

The probability that 2 out of the next ten customers will order the chef special is 0.3020. and this can be determined by using the binomial distribution.

Given :

20% of the patron's order the chef's special. Sample size, n = 10

To determine the probability formula of the binomial distribution is used, that is:

[tex]\rm P(x = r) = \; ^nC_r \times p^r \times (1 - p)^{n-r}[/tex]

Now, at n = 10 and r = 2, the probability is given by:

[tex]\rm P(x = 2) = \; ^{10}C_2 \times (0.2)^2 \times (1 - 0.2)^{10-2}[/tex]

[tex]\rm P(x = 2) = \; ^{10}C_2 \times (0.2)^2 \times (0.8)^{10-2}[/tex]

[tex]\rm P(x = 2) = \; \dfrac{10!}{(10-2)!\times 2!} \times (0.2)^2 \times (0.8)^{8}[/tex]

[tex]\rm P(x = 2) = \; 45 \times (0.2)^2 \times (0.8)^{8}[/tex]

P(x  = 2) = 0.3020

The probability that 2 out of the next ten customers will order the chef special is 0.3020.

For more information, refer to the link given below:

https://brainly.com/question/1957976

I NEED HELP ASAP PLEASE

Answers

Answer:

A and E

Step-by-step explanation:

B and D is unchangeable, species of bears and types of vegetables that existed in the world never changed.

C only consist of one data, temperature of Chicago at noon yesterday only.

Find the measures of angle 1 and 2.
110°
80°

Answers

Answer:

110 and 100

Step-by-step explanation:

Angle 2 will have the same messurement as the one across, so 110

Angle 1 will be the difference between 180 and 80, so 100

Help me please i need to hand this in

Answers

The answer is C

Hope this helps

On Friday night, the owner of Chez Pierre in downtown Chicago noted the amount spent for dinner for 28 four-person tables.
95 103 109 170 114 113 107 124 105 80 104 84 176 115 69 95 134 108 61 160 128 68 95 61 150 52 87 136
(a) Find the mean, median, and mode.
(b) Do these measures of center agree? Explain.
(c) Make a histogram or dot plot.
(d) Are the data symmetric or skewed? If skewed, which direction?

Answers

Answer:

median: 104.5

mean: 102.4

mode: 95

Step-by-step explanation:

Find the Area of the shaded region. Round your answer to the nearest tenth.

Answers

Answer:

210 ft^2

Step-by-step explanation:

The figure is made up of a rectangle 15 ft by 12 ft and a triangle with base 15 ft and height 4 ft.

A = LW + BH/2

A = (15 ft)(12 ft) + (15 ft)(4 ft)/2

A = 180 ft^2 + 30 ft^2

A = 210 ft^2

Answer:

210ft²

Step-by-step explanation:

Step one, find the area of the square. --->

A= bh (Area equals base times the height)

15×12=180

Step two, find the area of the triangle.

A=bh÷2 (Area equals base times the height divided by 2)

4×15= 60÷2= 30

Step three, add the solutions together

180+30=210

what is the percentile rank of 45 in the following length
24, 27, 27, 32, 34, 35, 35, 37, 38,41, 42, 44, 45, 45, 48, 49, 50, 52, 52

Answers

Answer:

63%.

Step-by-step explanation:

There are 12 scores below 45 and total number of scores = 19.

So percentile rank= (12/19) * 100

=  63%.

Can someone help with this problem please.

Answers

x = 19 yards = 57 feet
The ball is 57 feet from the hole.

Explanation:
The distance from the tee to the hole is 181 yards.

Using the Pythagoras Theorem,
x^2 + 180^2 = 181^2
x^2 + 32400 = 32761
x^2 = 361
x = sqrt(361)
x = 19 yards

1 yard = 3 feet
x = 19 yards = 57 feet

Need help with this scatter plots question. How do I solve it?

Answers

Answer:

No Trend

Step-by-step explanation:

Scatter plots usually have 1 or 2 outlier points if they're to show a positive or negative trend. There is a kind-of negative trend in the graph, but for me personally, I think the outliers kind of cancel the pattern out since there's way to much other points around it. It can't be constant since constant means that the points have to be in one place, and obviously its not really the case here. Therefore,  you're left with a no-trend graph!

Area of triangle with sides a=8, b= 10, c=7

Answers

Answer:

d equal 10 this is the answer

Do you have a picture. In order to calculate the area we could use the Area of a Triangle Formula of Heron’s Formula.

what is the value of b?

Answers

Answer:

24

Step-by-step explanation:

2b = b+24

2b-b = 24

b = 24

ten more than x times 6 is 11 more than y times 4

Answers

I’m supposing you are writing an equation for this. The equation could be written as 6x+10=4y+11.

Answer:

6x+10 = 4y+11

Step-by-step explanation:

6x+10 = 4y+11

The slope intercept form is:

y = 3/2x-1/4

if x is directly proportional to y and x= 4.5 when y = 3 find y when x = 24.

A) 63 B) 85 C) 16

Answers

x=4.5 - - -> y=3

x=24 - - - -> y= n

4.5n= 72

n= 72/4.5

n= 16

the answer is C) 16

X = 4.5

Y= 3

X=24

Answer: C) 16

Given that is directly proportional to (p-1)2 and p is always positive, find the
value of p when q = 80 , if 9= 30 when p = 7

A) 4
B) 6
Ch 10.82

Answers

Answer:

p = 10.8

Step-by-step explanation:

Given that p is directly proportional to (p-1)² and p is always positive, then;

q = k (p-1)²

If q = 30 and p = 7

30 = k(7-1)²

30 = 6²k

30 = 36k

5 = 6k

k = 5/6

To get p when q = 80

q =k (p-1)²

80 = 5/6((p-1)²

480 = 5(p-1)²

480/5 = (p-1)²

(p-1)² = 96

p-1 = √96

p-1 = 9.8

p = 9.8 + 1

p = 10.8

B) 6

Ch 10.82

The sum of two numbers is 12 . Their difference is 2 what are two numbers ?

Answers

Answer: 7 and 5

Step-by-step explanation:

I HOPE THIS HELPS

STAY SAFE!!!

Answer:

7 and 5

Step-by-step explanation:

7+5=12

7-5=2

Let 0 be an angle such that sec0= -13/12 and cot0<0. Find the exact values of tan0 and sin0.

Answers

Answer:

tan 0 = -2.4

sin 0 = 0.42

Step-by-step explanation:

sec 0 = -13/12 => cos 0 = -12/13

cot 0 < 0 => tan 0 < 0

so, the angle is on second quadrant

=> tan 0 = -12/5 = -2.4

=> sin 0 = 5/12 = 0.42

Answer:

Solution given;

Sec θ=-[tex]\frac{13}{12}[/tex]

cotθ< 0,

It lies in second quadrant.

where sin and cosec is positive.

Now

[tex] \frac{1}{cosθ}=-\frac{13}{12}[/tex]

cosθ=[tex]\frac{12}{13}[/tex]

[tex]\frac{b}{h}[/tex]=[tex]\frac{12}{13}[/tex]

b=12

h=13

By using Pythagoras law

p=[tex] \sqrt{13²-12²}=5 [/tex]

Now

exact values of tan θ=[tex]\frac{p}{b}[/tex]=[tex]\frac{5}{12}[/tex]

since it lies in II quadrant

tan θ=-[tex]\frac{5}{12}[/tex]

and

sinθ=[tex]\frac{p}{h}[/tex]=[tex]\frac{5}{13}[/tex]

since it lies in II quadrant

sin θ=[tex]\frac{5}{13}[/tex]

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