83 random samples were selected from a normally distributed population and were found to have a mean of 32.1 and a standard deviation of 2.4. Construct a 90% confidence interval for the population standard deviation.

Answers

Answer 1

Answer:

[tex]\frac{(82)(2.4)^2}{104.139} \leq \sigma^2 \leq \frac{(82)(2.4)^2}{62.132}[/tex]

[tex] 4.525 \leq \sigma^2 \leq 7.602[/tex]

Now we just take square root on both sides of the interval and we got:

[tex] 2.127 \leq \sigma \leq 2.757[/tex]

Step-by-step explanation:

Information given

[tex]\bar X=32.1[/tex] represent the sample mean

[tex]\mu[/tex] population mean (variable of interest)

s=2.4 represent the sample standard deviation

n=83 represent the sample size  

Confidence interval

The confidence interval for the population variance is given by the following formula:

[tex]\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma^2 \leq \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}[/tex]

The degrees of freedom given by:

[tex]df=n-1=8-1=7[/tex]

The confidence level is 0.90 or 90%, the value of [tex]\alpha=0.1[/tex] and [tex]\alpha/2 =0.05[/tex], and we can use excel, a calculator or a table to find the critical values.  

The excel commands would be: "=CHISQ.INV(0.05,82)" "=CHISQ.INV(0.95,82)". so for this case the critical values are:

[tex]\chi^2_{\alpha/2}=104.139[/tex]

[tex]\chi^2_{1- \alpha/2}=62.132[/tex]

The confidence interval is given by:

[tex]\frac{(82)(2.4)^2}{104.139} \leq \sigma^2 \leq \frac{(82)(2.4)^2}{62.132}[/tex]

[tex] 4.525 \leq \sigma^2 \leq 7.602[/tex]

Now we just take square root on both sides of the interval and we got:

[tex] 2.127 \leq \sigma \leq 2.757[/tex]


Related Questions

PLEASE HELP THIS IS SUPER URGENT

Answers

Answer:

13344yhgf567yf4edbui

Answer:

Choice: E

Step-by-step explanation:

Trust me

if i have 4 times the money of my brother. our totl is d dollars. how much money do each of us have?

Answers

Answers 5x=d that’s the answer nothing else

pls help w work!!!!!!!

Answers

Answer:

A: 55.5

Hoped this helped you! Please mark me brainiest if I am correct!

Solve the system of linear equations by substitution.

y=−4x−9
4x−y=1

Answers

Answer:

x=-1, y=-5 ---> (-1, -5)

Step-by-step explanation:

so you want to plug one equation into the other. so start off by plugging y=−4x−9 into the y value of   4x−y=1-----> 4x-(-4x-9)=1. now subtract and isolate x which ends up being x=-1. now plug the x=-1 into either equation and isolate and solve for your y value which ends up being y=-5. you can check you answer by plugging both the x and y you found into one equation and making sure the answer it gives is true. ;)

The solution for equations y=-4x-9 and y=-4x-9  is x=-1, y=-5.

What is an equation?

An equation is a combination of different variables, in which two mathematical expressions are equal to each other.

The given equations are,

y=-4x-9       (1)

4x-y=1        (2)

From equation (1), substitute the value of y in equation (2)

4x-(-4x-9)=1

8x+9=1

8x=-8

x=-1

Substitute x=-1 in equation (1),

y=-4(-1)-9

y=4-9

y=-5

The value of x is -1 and y is -5

To know more about Equation on:

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Solve for an angle in right triangles
T.T

Answers

Answer:

Angle A equals 59 degrees.

Step-by-step explanation:

sin^-1(6/7)=Angle A

Therefore, Angle A equals 59 degrees.

True / False
The square of 2.8 is 78.4
(step by step explanation)
answer fastly​

Answers

The answer is false.

The square of 2.8 is actually 7.83999 or 7.84 if rounded.

To get this, we simply bring 2.8 to the power of 2.

2.8 x 2.8 = 7.8399

Therefore, the answer would be false since the actual square of 2.8 is 7.84

Devon purchased one bag of dog food and three bags of cat food. Each bag of dog food weighs x pounds and each bag of cat food weighs half as much as the bag of dog food. The total weight of Devon's purchase is 32.5 pounds. The equation x+3(x/2)=32.5 can be used to determine the weight of the dog food and cat food. What is the weight in pounds of one bag of cat food?

Answers

Answer:

A pound of cat food will weigh 6.5 pounds

Step-by-step explanation:

Firstly, we need to get the value of x. Thus, let’s solve the equation at hand;

x + 3x/2 = 32.5

x + 1.5x = 32.5

2.5x = 32.5

x = 32.5/2.5

x = 13

Now from the question, we are made to know that a pound of cat food measures half of what a pound of dog food measures

Since we calculate a pound of dog food to weigh 13 pounds, a pound of cat food will weigh = 13/2 = 6.5 pounds

Find the surface area of the sphere shown below.

Answers

Answer:

I'd help you if you gave me the radius or the picture or the diameter...

Step-by-step explanation:

340 students went to the first school dance, the last school dance 306 students attended. What is the percent of change between the two dances?
(Please help

Answers

Answer:

10.59%

Step-by-step explanation:

percentage of change is given by

{(old number - new number)/old number} * 100

_________________________

given

no. of student  went to the first school dance = 340

no. of student  went to the last school dance = 306

Percentage of change between two dance

= ((no. of student  went to the first school dance - no. of student  went to the last school dance)/ no. of student  went to the fist school dance)*100

= (340 - 306)/340 *100

= (36/340 )*100 = 10.59%

The percent of change between the two dances 10.59%.

Please Help!
What is m

Answers

Answer:

"m" is used after a number to represent thaT

Step-by-step explanation:

Answer:

M is the alphabet which is representing the side of the triangle.

HOPE IT WILL BE HELPFUL FOR U

An ice cream parlor donated 6 containers of ice cream to a local elementary school. Each container holds 3 gallons of ice cream. If each student is served 1 cup of ice cream, how many students can be served?

Answers

Answer:

288 students can be served

Step-by-step explanation:

Looking at the donation made by the ice cream parlor, we want to know the number of students to be served.

We need to achieve a consistency in units first. What I mean by this is that all our units must be the same.

The parlor donated 6 containers with each container holding 3 gallons. The amount donated is thus 3 * 6 = 18 gallons of ice cream

Mathematically, there are 16 cups in a gallon. Thus, the amount of cups donated by the parlor would be 16 * 18 = 288 cups

Now since 1 student takes 1 cup of ice cream, the number of students that the donation can serve is 288/1 = 288 students

Help please! :/ I really need it!!

Answers

Answer:

the 2nd one

Step-by-step explanation:

whats 2+2 please fneviuqba

Answers

Answer:

4

Step-by-step explanation:

two plus two equals four

Answer:

4

Step-by-step explanation:

1+1+1+1=4

2+2=4

2*2=4

Bonnie had 5 cats that each weighed 6 2/5 pounds. How much do the cats weigh?

Answers

6 2/5 = 32/5 * 5 = 32 pounds

32 pounds because 6.4x 5=32.

Which line segment shows the hight that corresponds to the given base of the triangle
A
B
C

Answers

Answer:

The answer should be A.

Step-by-step explanation:

-The answer should be A, because the height has to be perpendicular to the base of the triangle and according to the following problem, line A shows the height of the triangle.

Can someone answer this question please please help me I really need it if it’s correct I will mark you brainliest .

Answers

Step 1) Divide the figure into shapes

Large rectangle: 5 x 12

Smaller rectangle: 4 x 6

Square: 2 x 2

Triangle: 4 x 3

Step 2) Find the area of each shapes

Large rectangle: A = 5 x 12 = 60

Smaller rectangle: A = 4 x 6 = 24

Square: A = 2 x 2 = 4

Triangle: A = 1/2 x 4 x 3 = 6

Step 3) Add all of the areas together

A = 60 + 24 + 4 + 6 = 94 square miles

Hope this helps! :)

50 POINTS! Carol is designing an artistic picture frame, which she wants to sell online. The picture frame will be square, but will come in several different sizes. She plans to place decorative stones around the outside of the picture frame. Carol’s first step was creating this prototype frame. (The first picture attached) You will be helping Carol form expressions that will tell her the number of stones she’ll need to order for each frame.

Part A:
How many stones make up the perimeter of the prototype picture frame? Perimeter is usually calculated by adding the length of each side of a shape. In the prototype, there are four stones per side. If we try to find the total number of stones in the frame by adding the number of stones per side, we’ll get an incorrect total. Why?

Part B:
Suppose that s equals the number of stones on one side of the picture frame. Write an expression that would give the number of stones in the top and bottom sides together.

Part C:
Write an expression in terms of s that represents the remaining stones. (The second attached picture) Write an expression in terms of s that represents the remaining stones.

Part D:
Now combine the two expressions you wrote in parts b and c by adding them together. What does the expression formed by this operation represent?










Answers

Answer: 12 stones

Step-by-step explanation:

The side of the length will be x = √m square inches.

What is the area of square and a rectangle?

The area of the square and rectangle is -

Square = [x]²           {x is the side of a square]

Rectangle = L x B    {L is the length and B is breadth}

here, we have,

Given is Lisa who is decorating outside edge of a square picture frame. She needs to know the side length of the frame. The area of the frame is [m] square inches.

It is given that the the area of the square is [m] square inches.

Assume that the length of the side is [x] inches.

x² = m

x = ±√m

Side cannot be negative.

Therefore, the side of the length will be -  x = √m

Therefore, the side of the length will be x = √m square inches.

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What does (x2−50x−600)÷(x−60) equal?

Answers

Answer:

x+10      x ≠ 60

Step-by-step explanation:

(x^2−50x−600)

----------------------

   (x−60)

Factor the numerator

(x-60)(x+10)

-------------------

(x-60)

Cancel the like terms

x+10

In a class 27 of students, 12 have a cat and 11 have a dog. There are 5 students who have a cat and a dog. What is the probability that a student has a dog given that they have a cat?

Answers

Answer:

41.67% probability that a student has a dog given that they have a cat

Step-by-step explanation:

We use the conditional probability formula to solve this question. It is

[tex]P(B|A) = \frac{P(A \cap B)}{P(A)}[/tex]

In which

P(B|A) is the probability of event B happening, given that A happened.

[tex]P(A \cap B)[/tex] is the probability of both A and B happening.

P(A) is the probability of A happening.

In this question:

Event A: having a cat.

Event B: having a dog.

12 of 27 students have a cat:

This means that [tex]P(A) = \frac{12}{27}[/tex]

5 students who have a cat and a dog.

This means that [tex]P(A \cap B) = \frac{5}{27}[/tex]

What is the probability that a student has a dog given that they have a cat?

[tex]P(B|A) = \frac{\frac{5}{27}}{\frac{12}{27}} = \frac{5}{12} = 0.4167[/tex]

41.67% probability that a student has a dog given that they have a cat

How to expand the following problem

Answers

Answer is 2 because it’s true

Quanto fa 5+5

Quanto fa 5+5

Answers

Answer:

10

Step-by-step explanation:

5+5=10

Answer:

5+5+ 10

Step-by-step explanation:

You can think of it as 5x2 which would get you 10 as the first way would too.

Write 7/18 as a decimal number. Round to two decimal places.

Answers

0.38 is 7/18 (filling space)

Answer:

0.388888889

Step-by-step explanation:

Please help!
You pick a card at random. Without putting the first card back, you pick a second card at random.

What is the probability of picking a 3 and then picking a 3?

Simplify your answer and write it as a fraction or whole number.

Answers

Answer:

The answer could be 0 or 1 out of 4, because choosing a card at first and not putting it back, then picking a second card at random, it would likely be one in zero attempts to pick 3 again but otherwise that it could be 1 out of 4 because it could be possible picking 3 at the first try.

Determine the probability of each event flipping a coin and getting heads


ANSWER ASAP

Answers

Answer:

A coin has 1 head and 1 tail.

=> Probability of flipping a coin and getting head: 1/2

Hope this helps!

:)

FP!!!!!!!!!!!!!!!

What is (10 x 10 ) + 50 + 1 =

Answers

look at the attached picture

Hope it will help you

Answer:

((2•5x10) +  50) +  1

 10x10 + 51 =

Answer: 151 :)

PLS HELP!

Which of the following questions are statistical questions? (more than one and assume the question is asked of the entire class)
A
How many dogs do you own?
B
How tall is Mrs. Zieroff?
C
What did you eat for dinner?
D
What were the ingredients in last nights soup?
E
How far did each paper airplane travel?

Answers

Answer:

A,C,E

Step-by-step explanation:

A statistical question has variability in the answer, so,

A=could range from any numbers providing a wide range of results

B=it's one answer (eg.5ft4) meaning a range can't be produced

C=could range from any food providing a wide range of results

D=One answer so no variations possible

E= could be a range of numbers

at a sale, costs were sold for $10 each. if the coats originally cost $20 each, what percentage of its original price was a coat sold for?

Answers

2% is the correct answer

Find the area of the trapezoid.
12
8
6

Answers

Answer:

The area of the trapezoid:

A = (base1 + base2) x height/2

  = (6 + 12) x 8/2

  = 18 x 4

  = 72

Hope this helps!

:)

PLEASE HELP which equation in the word bank can solve for x ?

Answers

Answer:

x + 10 = 24

Step-by-step explanation:

In the figure attached,

There are two external points A and B.

Fro point A two tangents AD and AE have been drawn and From point B tangents BE and BC have been drawn.

Since AD = 10 units,

Therefore, AE = 10 units

(Since tangents drawn from a point to a circle are same in measure, therefore, AD = AE)

Therefore,

BE = AB - AE

Since BE = BC

So BC = AB - AE

       x = 24 - 10

x + 10 = 24

Therefore, (x + 10) = 24 will be the equation to be used to solve for x.

2(2x - 1) = 10 i neeed help plz

Answers

Step-by-step explanation:

Here is the solution,mate. ☺️

Answer:

[tex]x = 3[/tex]

hope this helps

brainliest appreciated

good luck! have a nice day!

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