12. The local regional transit authority of a large city was interested in determining the mean
commuting time for workers who drive to work. They selected a random sample of 125
workers who drive to work and asked them how long they spent commuting to work in
minutes). A 95% confidence interval was constructed and reported as (27.74, 30.06).
(a) Show that the conditions for calculating a confidence interval for a mean are satisfied.
(b) Interpret the interval in the context of this problem.

Answers

Answer 1

1. We conclude that the conditions for calculating a confidence interval for a mean are satisfied.

2. Since interval was constructed and is reported, we assume that distribution of the sample mean is normal.

Do the conditions for a mean confidence interval calculation hold?

Let x be the sample mean

Let s be the sample standard deviation

Let n be the sample size

Let α be the significance level

Let Z be the standard normal distribution value.

To determine if conditions for calculating confidence interval for a mean are met, we have to check the followings:

1. Random sampling:

The sample of 125 workers was selected randomly.

2. Independence:

We assume that each worker's commuting time is independent of each other.

3. Sample size:

n = 125 > 30. This satisfies the condition for the central limit theorem to apply.

4. Normality:

The 95% confidence interval was constructed using the formula x ± Zα/2(s/√n).

Since interval was constructed and is reported, we can assume that the distribution of the sample mean is approximately normal. Therefore, we can conclude that the conditions for calculating a confidence interval for a mean are satisfied.

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Related Questions

Please help I need it!!!

Answers

Answer:

I think it is the first one i think

Step-by-step explanation:

complete the conversion:
5 grams / metres squared = _________ kilograms / hectares
(5g/m2=_________ kg/ha)

Answers

Answer:

5 grams/metres squared = 50 kg/hectares

Step-by-step explanation:

We need to convert 5 grams/metres squared to kilograms/hectares.

We know that,

1 kg = 1000 g

1 hectare = 10000 m²

So,

[tex]5\ \dfrac{g}{m^2}=5\times \dfrac{0.001}{\dfrac{1}{10000}}\\\\=50[/tex]

Hence, 5 grams/metres squared = 50 kg/hectares

A caterer charges a setup fee of $50, plus $20 per person How much will the caterer charge if 35 people attend the party, and the customer has a coupon for $100 discount off the total?

Answers

They will charge $165 for each person
The answer is 650

20x35= 700

700+50 = 750

750-100= 650

Jacqui likes to travel to the beach on weekends. She starts at her house, drives d miles, and then spends t hours walking the remaining w miles to get to the beach. Jacqui drives three times as long as she walks during the trip. The equation below represents Jacqui's average speed, a, in miles per hour, when traveling to the beach. a=d+w/3t+t What is the meaning of 3t + t3t+t in the equation above? -The total time that Jacqui spends traveling to the beach -The time that Jacqui spends driving to the beach -The total distance that Jacqui travels to the beach -Jacqui's maximum speed during her trip Jacqui's average speed during one trip to the beach was 3636 miles per hour. If Jacqui drove 70 miles and the entire trip to the beach took her 22 hours, how many miles did she walk to get to the beach?

Answers

Answer:

The answer is below

Step-by-step explanation:

1) Average speed is the ratio of the total distance travelled to the total time taken. Hence it is given by:

Average speed = total distance / total time

Total distance = d miles + w miles

Jacqui drives three times as long as she walks during the trip, hence:

time spent driving = 3t

Total time = 3t + t

Average speed = total distance / total time

a = (d + w) / (3t + t)

2) (3t + t) represents the total time that Jacqui spends traveling to the beach.

3) Given that a = 36 miles per hour, total time = 2 hours

a = total distance / total time

36 miles per hour = total distance / 2 hours

total distance = 72 miles

Total distance = distance walk + distance drove

72 = distance walk + 70

Distance walk = 2 miles

Please help I’ll give brainliest

Answers

Answer:

33

Step-by-step explanation:

The formula for solving the area of a Trapezoid is a+b/2*h if we substitute the value to 16+3/2*3 it will equal 33

Find two integers whose sum is 5 and product is -66 TWO INTEGRES
NOT 1 TWO

Answers

Answer:

-6 and 11

Step-by-step explanation:

The only factors of 66 are 11, 6, 2 and 3

11*6 is the only pair whose product is 66

The difference betwen 11 and 6 is 5

11 must be positive and 6 negative since the sum is positve

Which one is it?
a) <
b) =
c) >

Answers

Answer:

A: less that

Step-by-step explanation:

4( 14)+3

36+3= 39

39 (2+9)6-7

(11)6-7

66-7

59

39<59

Please help me with this question!!

Answers

Answer:

ok so for g times h you would have to foil it and then you would multiply it by f of X

What’s the line of y= -1/2x+2

Answers

Answer:

A picture of the graph is attached

Step-by-step explanation:


If you rolled two dice, what is the probability
that you would roll a sum of 12?
Give your answer as a simplified fraction, Enter
the number that belongs in the green box.
second
first
1 2 4 5 6
11,1 1,2 1,3 1,4 1,5 1,6
212,1 2,2 2,3 2,4 2,5 2,6
33,1 3,2 3,3 3,4 3,5 3,6
44,1 4,2 4,3 4,4 4,5 4,6
5 5,1 5,2 5,3 5,4 5,5 5,6
6 6,1 6,2 6,3 6,4 6,5 6,6

Answers

Probability is 1/36.

What is probability?

The probability is defined as the possibility of an event to happen is equal to the ratio of the number of outcomes and the total number of outcomes.

Two dices were rolled.

Total outcomes in sample space: S = 36

Outcomes which have sum as 12 are E = {(6,6)}

Required Probability: P(E)= 1/36

Hence, Probability is 1/36 of which have sum as 12

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Answer:

1/36

Step-by-step explanation:

Use the following function rule to find f(8). f(x) = (-4 + x)2
f(8) =​

Answers

Answer:

16

Step-by-step explanation:

f(x) = (-4 + x)^2

Let x=8

f(8) = (-4 + 8)^2

Parentheses  first

     = 4^2

Then powers

    = 16

A company sells widgets. The amount of profit, y, made by the company, is related to
the selling price of each widget, x, by the given equation. Using this equation, find out
what price the widgets should be sold for, to the nearest cent, for the company to
make the maximum profit.
y = -x2 + 72x – 458

Answers

Answer:

In order to make the maximum profit, the company should sell each widget at (the currency isn't given, so I'll be assuming USD) $36.

Step-by-step explanation:

The amount of profit y made by the company from selling each widget at x price is modeled by the equation:

[tex]y=-x^2+72x-458[/tex]

Since this is a quadratic with a negative leading coefficient, its maximum will occur at its vertex point. We want to find the price that the widget should be sold to make the maximum profit. So, we want to find the x-coordinate of the vertex. This is given by the formula:

[tex]\displaystyle x=-\frac{b}{2a}[/tex]

In this case, a = -1, b = 72, and c = -458. Substitute and evaluate:

[tex]\displaystyle x=-\frac{72}{2(-1)}=36[/tex]

In order to make the maximum profit, the company should sell each widget at (the currency isn't given, so I'll be assuming USD) $36.

Find the angle for this problem

Answers

Answer:

ans: 31°

Step-by-step explanation:

<EFG = <EFH + <HFG

2x+52= 21 + ( x+31)

2x-x= 21 +31 -52

x= 0

so our question is to find <HFG so,

x+31°= 31°

please help! 10 points, thank you

Answers

Answer:

261.5 ft^2

Step-by-step explanation:

Surface Area of a rectangular prism = Length x Width x Height

= 8.5ft x 6ft x 5.5ft

= 261.5 ft

Calculate the sizes of the unknown angles in each diagram.

Please, answer with explanation.

Answers

Step-by-step explanation:

a) 2z+3z+4z=180

9z=180

z=20

So,three angles are 40,60 and 80

b) (y+30)+(2y+80)+(y+10)=180

y+30+2y+80+y+10=180

4y+120=180

4y=60

y=15

Three angles are 45,110,25

Please answer correctly !!!!! Will mark Brianliest !!!!!!!!!!!!!!

Answers

Answer:

Step-by-step explanation:

the formula is C=2√πA

so simplifying that would give us c=2(4π)

simplify again and we get c=8π

ahhh help its PLATO
'la

Answers

Answer:

D

Step-by-step explanation:

To find the inverse of a function, first replace f(x) with y.

Next, switch all the x's and y's, and then solve for y.

Finally, replace y with f-1(x).

Find the equation of the line for each situation.

a line with a y - intercept of 4 and a slope of -1
a line passing through the point (3, 4) and having a slope of -2
a line passing through the points (1, -1) and (9, 3)

Answers

Step-by-step explanation:

1) y = -x+4

2) y-4= -2(x-3)

y = -2x+6+4

y = -2x+10

3) slope = (3+1)/(9-1) = 4/8=½

the Equation =>

y+1= ½(x-1)

y = ½x -½-1

y = ½x - 1½ or 2y = x -3

A scale drawing of Elizabeth's rectangular room is 4 inches by 7 inches. The scale is 1 inch = 3 feet. What is the area, in square feet, of Elizabeth's room?

Answers

Answer:

84 feet

Step-by-step explanation:

4 inches× 7 inches=28inches

28 inches×3feet=84feet

Perez throws a stone on the pond. The path traveled by the stone can be modeled by y = -2x2 + 8x + 5, where x represents the time (in seconds) and y represents the height of the stone (in feet). What is the maximum height that the stone reaches

Answers

Answer:

The maximum height that the stone reaches is of 26 feet.

Step-by-step explanation:

Vertex of a quadratic function:

Suppose we have a quadratic function in the following format:

[tex]f(x) = ax^{2} + bx + c[/tex]

It's vertex is the point [tex](x_{v}, y_{v})[/tex]

In which

[tex]x_{v} = -\frac{b}{2a}[/tex]

[tex]y_{v} = -\frac{\Delta}{4a}[/tex]

Where

[tex]\Delta = b^2-4ac[/tex]

If a<0, the vertex is a maximum point, that is, the maximum value happens at [tex]x_{v}[/tex], and it's value is [tex]y_{v}[/tex].

y = -2x2 + 8x + 5

Quadratic function with [tex]a = -2, b = 8, c = 5[/tex]

What is the maximum height that the stone reaches?

y value of the vertex. So

[tex]\Delta = 8^2-4(-2)(5) = 64 + 40 = 104[/tex]

[tex]y_{v} = -\frac{104}{4(-2)} = 26[/tex]

The maximum height that the stone reaches is of 26 feet.

ABCD is a trapezium in which AB ∥ CD, AD ⊥ DC, AB = 4 cm, BP = 7 cm and DC = 25 cm, then area of the trapezium is 45.

Answers

Question:

ABCD is a trapezium in which AB ∥ CD, AD ⊥ DC, AB = 4 cm, BP = 7 cm and DC = 25 cm, then area of the trapezium is ____.

Answer:

101.5cm²

Step-by-step explanation:

The figure for the trapezium ABCD is attached to this response.

To find the area of the trapezium, we use the formula for calculating the area of a trapezium given as follows;

A  = [tex]\frac{1}{2}[/tex] x (a + b) x h            ------------------(i)

Where;

A = area of the trapezium

a and b are the parallel sides of the trapezium

h = height of the trapezium.

As shown in the figure,

AB and CD are parallel

Therefore, we can say that;

a = AB

b = CD

Also, from the figure,

The height of the trapezium is BP

Therefore, we can say that;

h = BP

We know that;

a = AB = 4cm

b = CD = 25cm

h = BP = 7cm

Substitute these values of a, b and h into equation (i) as follows;

A  = [tex]\frac{1}{2}[/tex] x (4 + 25) x 7    

A  = [tex]\frac{1}{2}[/tex] x (29) x 7    

A = 101.5

Therefore, the area of the trapezium is 101.5cm²

I will give 25 points for it if solve this problem ​

Answers

Answer:

5/27

30/81 = 10/17

it's just ratios but if you need then vice versa, swap numerator and denominator

Answer:

the person on top is correct :)

Step-by-step explanation:

What is the missing number? I’ll mark brainly

Answers

Answer:

I think it is 4

I am not sure about it

Which expression is equivalent to
(3m² + 5m - 2) + (-2m +18)?
Someone answer ASAP

Answers

3m^2 +5m-2-2m+18

3m^2 +3m+16

Answer:

3m² + 3 m + 16

Step-by-step explanation:

( 3 m ² + 5 m - 2 ) + ( - 2m + 18 )

Remove the unnecessary parantheses and rewrite

3 m ² + 5 m - 2 - 2 m + 18

combine like terms

3m² + 5 m - 2 m + 18 - 2

calculate the sum

3m² + 3 m + 16

What is the sign of -x/-y when x > 0 and y > 0?

Answers

Answer:

pretty sure its positive

Step-by-step explanation:

hope this helps, have  a great day!

Answer:

A is correct

Step-by-step explanation:

if we know that both x and y are positive, they are both going to be negative

and since we know that, -x divided by -y is the same as saying something negative divided by something negative which is ALWAYS positive because negatives cancel out leaving the answer positive something, something

factorize: 9x^2 - 24xy + 16y^2

Answers

9x²-24xy+16y²

(3x)²-2.(3x)(4y) +(4y)²

(3x-4y)²

(3x-4y)(3x-4y)

Answer:

[tex](3x -4y)^2[/tex]

Step-by-step explanation:

[tex]9x^2 - 24xy + 16y^2 = (3x)^2 - 24xy + (4y)^2[/tex]

                           [tex]=(3x)^2 -2(3x \times 4y) + (4y)^2\\[/tex]

a = 3x , b = 4y . The expression [tex]a^2 - 2ab + b^2 = (a-b)(a-b) =(a-b)^2[/tex]

                           [tex]=(3x -4y)(3x - 4y)[/tex]

[tex]9x^2 - 24xy + 16y^2 = (3x -4y)^2[/tex]

                           

El profesor Héctor y sus alumnos organizaron una excursión a
la Ciudad de México. Visitarán el Centro Histórico, el Castillo de
Chapultepec y el Museo de Antropologia. El costo del transporte
por alumno es de $310.75 y no incluye alimentos.
a) Para pagar el transporte, el profesor Héctor tiene que juntar
el dinero de los 37 alumnos que participaran en la excursion
¿Cuánto dinero debe reunir?​

Answers

Answer:

$8.39 por pe rsona

Step-by-step explanation:

if x= 3-2^2 then find the value of x^2+1÷x^2​

Answers

X = 3-2^2

Simplify x:

3-4 = -1

X = -1

Replace x in the equation and solve:

(-1) ^2 + 1 /(-1)^2

(-1)^2 = 1

Simplify to get 1 + 1/1 = 1+ 1 = 2

The answer = 2

The function C(x) = 400x - 0.2x ^ 2 represents the total costs for a company to produce a product, where in dollars and x is the number of units sold. Which statement is true? is the total cost

Answers

Answer: it b y’all

Step-by-step explanation: I took the test

Answer:

B

Step-by-step explanation:

To determine the maxima and minima of the polynomial, differentiate the given based on x and equate to 0.                                   C(x) = 400x - 0.2x²                               dC(x) / dt = 400 - 0.4 x = 0 The value of x is 1000. This is the value of the maxima. As the value of C(x) continously becomes lesser as the value of x is set higher, the minima is not identified. Substitute x to the original equation,                               C(x) = (400)(1000) - 0.2(1000²) = $ 200,000Thus, the answer is letter B. 

I need this ASAP. Thanks​

Answers

Answer:

-6

Step-by-step explanation:

since x = - 5 is < 3

for x < 3,

f(x) = 3x + 9

placing the value of x as - 5

f(x) = 3× (-5) + 9

= -15 + 9

= - 6
Other Questions
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