Let X and Y equal the concentration in parts per billion of chromium in the blood for healthy persons and for persons with a suspected disease, respectively. Assume that the distributions of X and Y are normal. A sample of 8 observations for X have a sample mean of 15.75 and a sample variance of 46.21. A sample of 10 observations of Y have a sample mean of 23.3 and a sample variance of 92.68. Find a 90% confidence interval for the ratio of variances,

Answers

Answer 1

Answer:

The value is  [tex]0.152 \le \frac{\sigma_1^2}{\sigma_2^2} \le 1.835[/tex]

Step-by-step explanation:

From the question we are told that

  The number of observation for X  is [tex]n_1 = 8[/tex]

  The sample mean for X  is  [tex]\= x _1 = 15.7 5[/tex]

  The sample variance for X is [tex]s^2_1 = 46.21[/tex]

   The number of observation for Y  is [tex]n_1 = 10[/tex]

  The sample mean for Y  is  [tex]\= x _1 = 23.3[/tex]

  The sample variance for Y is [tex]s^2_1 = 92.8[/tex]

Generally the degree of freedom for X is      

     [tex]df_1 = n_1 - 1[/tex]

=>  [tex]df_1 = 8 - 1[/tex]

=>  [tex]df_1 = 7[/tex]

Generally the degree of freedom for X is      

     [tex]df_2 = n_2 - 1[/tex]

=>  [tex]df_2 = 10 - 1[/tex]

=>  [tex]df_2 = 9[/tex]

From the question we are told the confidence level is  90% , hence the level of significance is    

      [tex]\alpha = (100 - 90 ) \%[/tex]

=>   [tex]\alpha = 0.10[/tex]

=>  [tex]\frac{\alpha}{2} = \frac{0.10}{2}[/tex]

=>  [tex]\frac{\alpha}{2} = 0.05 }[/tex]

Generally the 90% confidence interval for the ratio of variances is mathematically represented as

     [tex]\frac{s_1^2}{s_2^2 } * \frac{1}{F_{ 1 - \frac{\alpha }{2} , df_1 , df_2 }} \le \frac{\sigma_1^2}{\sigma_2^2} \le \frac{s_1^2}{s_2^2 } * \frac{1}{F_{ \frac{\alpha }{2} , df_1 , df_2 }}[/tex]

=>  [tex]\frac{46.21}{92.68 } * \frac{1}{F_{ 1 - 0.05 , 7 , 9 }} \le \frac{\sigma_1^2}{\sigma_2^2} \le \frac{46.21}{92.68 } * \frac{1}{F_{ 0.05 , 7 , 9 }}[/tex]

=>  [tex]\frac{46.21}{92.68 } * 0.304 \le \frac{\sigma_1^2}{\sigma_2^2} \le \frac{46.21}{92.68 } * 3.677[/tex]

=>  [tex]0.152 \le \frac{\sigma_1^2}{\sigma_2^2} \le 1.835[/tex]


Related Questions

Which investment would be worth the MOST after 20 years?
A) An initial investment of $3000 compounded annually at a rate of 12%
B) An initial investment of $3000 compounded quarterly at a rate of 11.9%
C) An initial investment of $3000 compounded weekly at a rate of 11.85%
D) An initial investment of $3000 compounded continuously at a rate of 11.8%​

Answers

Answer:

D)  An initial investment of $3000 compounded continuously at a rate of 11.8%​

Step-by-step explanation:

What is the decimal multiplier to decrease by 2.7%?

Answers

Multiplying by 1 keeps it the same. A number greater than 1 would be an increase and a number below 1 would be a decrease.

The decrease is 2.7% which is written as 0.027 as a decimal.

Subtract that from 1:

1 - 0.027 = 0.973

The multiplier would be 0.973

how many millilmeters are in 3 gallons

Answers

Answer:

11,356 ml.....................

according to the internet, 11356235.4

The area of a square shaped park measures 16900 square feet. How many feet of fencing would be needed to enclose that park?

Answers

Answer:

520 feet

Step-by-step explanation:

The area=16900

Area formula=b^2

b^2=16900

square root of 16900=130

130*4=520

Are the following equations parallel, perpendicular, or neither? y= 3x - 1 and y =
-1/3x + 10 *
Parallel
Perpendicular
Neither

Answers

Answer:

Perpendicular

Step-by-step explanation:

Please help I will mark brainliest

Answers

Answer:

a)(2x+1)² - 3

4x² + 4x + 1 - 3

4x² + 4x - 2

4(-2)² + 4(-2) - 2

16 - 8 - 2

6 (final answer)

b) 4(3)² + 4(3) - 2

36 + 12 - 2

46 ( final answer)

c) 2(x²-3) + 1

2x² - 6 + 1

2(3)² - 5

18 - 5

13(final answer)

Mrs. Liang, the librarian, wants to compare the numbers of patrons who prefer e-books to paperback books. She decides to take a poll of every third adult with a child who arrives at the library for one of the four reading groups: toddlers, preschoolers, primary grades, and upper elementary. Which statement is true about her method of data collection?

Answers

Answer:

a

Step-by-step explanation:

She surveys adults with a child , preschoolers , Primary students, and upper elementary Students , and these are the majority of all the people that go to the library.

(it was also correct when i took it on Edge(nuiy!)

I hope this helped you a bit!!!!

Answer:

A

Step-by-step explanation:

What is the quotient for 6 divided by 2/3

Answers

Answer:

9

Step-by-step explanation:

change 6 into 6/1

6/1 times 3/2 cause you switch around the two and three and change it to multiplication

6 times 3 = 18

2 times 1 = 2

18/2 = 9/1 = 9

Evaluate the function at the given value. f(a) = a^3 + 5a^2 + 10a + 12 at a = -2​

Answers

Answer:

4

Step-by-step explanation:

What is the perimeter of the triangle?



a
84 in
b
94 in
c
74 in
d
64 in

Answers

Answer:

The answer is C

Step-by-step explanation:

We alsreadyknow that 37 and 12 is the 2 given lines.  and  The last line is not 37 but pretty close making C the answer.

Answer:

D) 64 In

Step-by-step explanation:

P=12+37+64

Plzzz answer it :( :

All fraction or mixed number answers are in simplest form or reduced form .

True or false

Answers

Answer:

false it is not always reduced form

false it doesn’t always have to be reduced

write the equation for the line that is parallel to y=2/3x-5 and goes through the point (-12/2)

Answers

Answer:

I put the equation into Point-Slope Form and got:

y - 2 = 2/3(x + (-12))

Distribute the 3 to the numbers on the left:

3y - 6 = 2(x - 12)

Multiply the Parenthesis by 2:

3y - 6 = 2x - 24

Add 6 to the right side:

3y = 2x - 18

Divide both sides by 3:

y = 2/3x - 6 is the answer :)

So this is just an easy substitution problem. We want to start off writing the question y= 2/3x-5 and then off to the side writing (-12, 2) labeling -12 as X and 1 as Y. Then we want to pick whether we want to solve for X or y first (it doesn’t matter) I chose to solve for X first but to solve for x you need to substitute 2 in from the given pair that was given to you. You replace Y in the original equation with 2 and then solve the equation as normal, add like pairs (add five to each side, we’re trying to get x alone), then you have 7= 2/3x, divide 2/3 on each side and you’ll get X= 10.5. So now we have to solve for Y, to solve for Y we need to replace the X in the original equation (y= 2/3x- 5) for -12 in the given pair that was given to you. So you’ll have Y= 2/3(-12) -5, now filling pemdas we’ll multiply 2/3 and -12 and get -8 then we subtract 5 from -8 and we get Y= -13. So our final answer should always be in an ordered pair, we should have (10.5, -13) as the final answer.

Sam and Larry’s Ice Cream Shoppe sells the following sizes of ice cream cones: single at $0.89, double at $1.19; triple at $1.39. One day, Danielle sold 52 ice cream cones. She sold two more than twice as many doubles as triples. If she sold $58.98 in cones, how many of each size did she sell?

Answers

9514 1404 393

Answer:

17 singles24 doubles11 triples

Step-by-step explanation:

Let s, d, t represent the numbers of singe, double, and triple cones sold. The problem statement tells us three relationships.

  s + d + t = 52 . . . . . . Danielle sold 52 cones one day

       d -2t = 2 . . . . . . . doubles is 2 more than twice the number of triples

  0.89s +1.19d +1.39t = 58.98 . . . . total amount of sales

__

There are many ways to solve this set of equations. A graphing calculator can quickly tell you the solution is ...

  (s, d, t) = (17, 24, 11)

__

If you want to solve this by hand, it may work well to use substitution.

The second equation gives an expression for d:

  d = 2t +2

The first equation gives an expression for s that can be written in terms of t.

  s = 52 -d -t

  s = 52 -(2t +2) -t = 50 -3t

Using these in the last equation, we have ...

  0.89(50 -3t) +1.19(2t +2) +1.39t = 58.98

  1.10t = 12.10 . . . . . . . . collect terms, subtract 46.88

  t = 11 . . . . . . . . . . . . . . divide by 1.10

  d = 2(11) +2 = 24

  s = 50 -3(11) = 17

Danielle sold 17 singles, 24 doubles, and 11 triple cones.

Please helppp!! I suck at math

Answers

Answer:

5/6−1/9=13/18

Step-by-step explanation:

The fractions have unlike denominators. First, find the Least Common Denominator and rewrite the fractions with the common denominator.

Multiply both the numerator and denominator of each fraction by the number that makes its denominator equal the LCD. This is basically multiplying each fraction by 1.

(5/6×3/3)−(1/9×2/2)=?

Complete the multiplication and the equation becomes

15/18−2/18=?

The two fractions now have like denominators so you can subtract the numerators.

Then:

15−2/18=13/18

This fraction cannot be reduced.

Therefore:

5/6−1/9=13/18

how many cookies will Julie make in 7 days?

Answers

Answer:

700 cookies

Step-by-step explanation:

that's easy but there you go

Answer:

700 cookies in 7 days

Step-by-step explanation:

So do you have to have a least 2 people answering the question to five them the crowm?

Answers

Answer:

Well... only two people can answer a question. But you must have both two answers for a question to give brainliest to one or another. Got it? :)

Step-by-step explanation:

James borrows $4,200 to pay his college tuition. He signs a 5-year simple interest loan. If the monthly payments are $78.40, what is the interest rate on the loan?

Answers

Answer:

2.4%

Step-by-step explanation:

Total amount of payments:

5 years * 12 months/year * $78.40/month =

= $4704.00

Amount of interest paid in 5 years:

$4704 - $4200 = $504

Amount of interest paid in 1 year:

$504/5 = $100.80

Annual percent rate of interest:

$100.80/$4200 * 100% = 2.4%

Answer: 2.4%

Solve for the complimentary angle b

Answers

Answer:

b = 38

Step-by-step explanation:

The two angles form a 90 degree angle so they add to 90

b+52 = 90

Subtract 52 from each side

b+52-52 =90-52

b = 38

Answer:

38

Step-by-step explanation:

90-52=38

and the little box indicates it's a right angle which is 90 degrees

Please give me the correct answer ​

Answers

3 × 10-⁵

Because here there are 5 zeroes so 0.00003 can be written as 3/100000 , here 100000 = 10 . Now , 3/10 3 × 1/10 3 × 10-

Hence , 0.00003 = 3 × 10- . So it is -5

Sharon runs a screen-printing business. To print T-shirts each day, it costs her $200 in labor plus $5 per T-shirt for materials. Her income is $15 for each T-shirt she sells. How many T-shirts does Sharon need to sell each day in order for her costs to equal her income for that day?


(i mainly need the equation for this problem)

Answers

Answer:

Equation: 15n = 200 + 5n

Number of T-shirts: 20

Step-by-step explanation:

We need to find an expression for the costs for 1 day for making n number of T-shirts and an expression for the income for 1 day for selling n number of T-shirts. Then we set the expressions equal and solve for n, the number of T-shirts.

Expenses in 1 day:

The expenses are a fixed cost of $200 plus the cost per T-shirt.

$200 plus $5 per T-shirt

We need an expression for the cost per T-shirt in terms of n, the number of T-shirts.

If she makes 1 T-shirt, she spends $5 * 1.

If she makes 2 T-shirts, she spends $5 * 2.

If she makes n T-shirts, she spends $5 * n, or simply 5n.

Her total costs for a day are:

200 + 5n

Income in 1 day:

All the income comes from selling T-shirts.

She sells 1 T-shirt for $15 * 1.

She sells 2 T-shirts for $15 * 2.

She sells n T-shirts for $15 * n, or simply 15n

Her total income for 1 day is:

15n

Now we set the costs equal to the income and solve for n.

15n = 200 + 5n           <---------   here is the equation you need

Subtract 5n from both sides.

10n = 200

Divide both sides by 10.

n = 20

Answer: She needs to sell 20 T-shirts.

Please help me with both the questions ty.

Answers

Answer:

4) 26+4/842-/×375-^×

5)/^9+37+×+454+12

Step-by-step explanation:

Given the quadratic equation: 1/2x^2+3x−10=0

Answers

Answer:

x=2.3851648071345037,−8.385164807134505

Step-by-step explanation:

PLEASE HELP !!!!!

1) Find the equation of the trend line (line of best fit). SHOW WORK

2) Predict the number of tips that would be collected if 100 costumers were served at the restaurant on a given day. Explain your reasoning.

3)EXPLAIN how to use the regression calculator to make a reasonable prediction given a data table

(I don't know how to attach more than 1 picture by the way )​​

Answers

Answer:

1) y = 1.8741176487x + 3.655964863

2) About $191 using the equation, about $180 or more using the data you are given.

3) I can use the regression calculator by using the largest number of customers you have in the data set and lowest number of customers and compare them to see if the numbers are in ascending or descending order.

please answer, what is the solution of the system below? how do you know?

Answers

Answer:

(1,3)

Step-by-step explanation:

The solution is where the two lines intersect.

In this graph, it's (1,3)

god please help me i’ve been stuck on this problem for hours and i’m so hungry:(

Answers

Answer:

B

Step-by-step explanation:

u should go eat

Answer:

A)

because it passes the line twice instead of once

(fuctions only cross once)

hope that helped you:)

please make my answer brainiest as im trying get 3 brainiest answers

What is the approximate percent of decrease from 90 to 40?

Answers

The answer to the question is 45%

How do you work this problem? 10x2 +25x

Answers

Answer:

x=-5/2,0

Step-by-step explanation:

It is solved by first factorizing it

10x²+25x=5x(2x+5)=0

Finding the zeros

5x=0x=0/5=0

2x+5=0

x=-5/2

Therefore x is -5/2 or 0

Help me out in this question please

Answers

Answer:

The answer is D

Step-by-step explanation:

Which multiplication problem does the model represent?

A- 1/8 times 2

B- 7/8 times 2

C- 1/2 times 4

D- 1/4 times 8

The correct answer would be D- 1/4 times 8

This is the correct answer because if you look at the model, it shows 2 blocks of 1, and then 8 blocks of 1/4, which both equal 2, and the model does not say anything about the top row, only the bottom, and after process of elimination, you would be left with 1/4 times 8

Bryson can travel 28 1/4 miles in 1/2 hour. What is his average speed in miles per hour?

Answers

Answer:

56 if rounding but 56.50 if not

Step-by-step explanation:

rate

B=14 what is 3b-5
Please help me someone

Answers

Answer:

37

Step-by-step explanation:

14×1

24×2

42×3

42-5 = 37

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