The management of a large airline wants to estimate the average time after takeoff taken before the crew begins serving snacks and beverages on their flights. Assuming that management has easy access to all of the information that would be required to select flights by each proposed method, which of the following would be reasonable methods of stratified sampling?

a. For each day of the week, randomly select 5% of all flights that depart on that day of the week.
b. Divide all flights into the following 4 groups on the basis of scheduled departure time: before 9:00 am 9:00 am to 1:00 pm. 1:00 pm to 5:00 pm, and after 5:00 pm. Randomly select 5% of the flights in each group.
c. For each crew member the airline employs, randomly select 5 flights that the crew member works.
d. Divide the airports from which the airline's fights depart into 4 regions: Northeast, Northwest Southwest and Southeast. Randomly select 5% of all flights departing from airports in each region

Answers

Answer 1

Answer:

The answer is "Option a, Option b, and Option d".

Step-by-step explanation:

In the given question it is used to stratifying the sampling if the population of this scenario it flights takes off when it is divided via some strata.

In option a, In this case, it stratified the sampling, as the population of planes taking off has been divided into the days of the week. In option b, It also used as the case of stratified sampling. In options c, it is systematic sampling, that's why it is wrong. In option d,  It is an example of stratifying the sampling.
Answer 2

Answer:

For each day of the week, randomly select 5% of all flights that depart on that day of the week.

Divide all flights into the following 4 groups on the basis of scheduled departure time: before 9:00 am, 9:00 am to 1:00 pm, 1:00 pm to 5:00 pm, and after 5:00 pm. Randomly select 5% of the flights in each group.

Divide the airports from which the airline's flights depart into 4 regions: Northeast, Northwest, Southwest, and Southeast. Randomly select 5% of all flights departing from airports in each region.

Step-by-step explanation:

ll sampling methods that divide the flights into a small number of mutually exclusive categories are appropriate. These methods include all flights on the basis of a characteristic that might be associated with the variable being investigated and randomly selects a proportionate number of flights from each group.


Related Questions

C 89. What is the power of 5, so that 1 its value become ? (५ को घाताङ्क 25 कति हुदा त्यसको मान 25 हुन्छ ?) .7​

Answers

C 89. What is the power of 5, so that 1 its value become ?

The power is 0. because if 0 is tge powwe of any variable or letters the value becomes 1.

Cual es el capital que prestado al 10% bimestral durante 6 meses y 10 días produce un interés de 1140

Answers

Answer:

El capital que prestado al 10% bimestral durante 6 meses y 10 días produce un interés de $1140 es $3,600.

Step-by-step explanation:

Para determinar cuál es el capital que prestado al 10% bimestral durante 6 meses y 10 días produce un interés de $1140 se debe realizar el siguiente cálculo:

6 / 2 = 3

10/60 = 0.16666

10 x 3.1666 = 31.666

31.666 = 1140

100 = x

100 x 1140 / 31.666 = X

114,000 / 31.666 = X

3,600 = X

Por lo tanto, el capital que prestado al 10% bimestral durante 6 meses y 10 días produce un interés de $1140 es $3,600.

There are five cities in a network. The cost of building a road directly between i and j is the entry ai,j in the matrix below. An infinite entry indicates that there is a mountain in the way and the road cannot be built. Determine the least cost of making all the cities reachable from each other.

0 3 5 11 9
3 0 3 9 8
5 3 0 [infinity] 10
11 9 [infinity] 0 7
9 9 10 7 0

Answers

Solution :

Given :

There are five cities in a network and the cost of [tex]\text{building}[/tex] a road directly between [tex]i[/tex] and [tex]j[/tex]  is the entry [tex]a_{i,j}[/tex]

[tex]a_{i,j}[/tex]  refers to the matrix.

Road cannot be built because there is a mountain.

The given matrix :

[tex]\begin{bmatrix}0 & 3 & 5 & 11 & 9\\ 3 & 0 & 3 & 9 & 8\\ 5 & 3 & 0 & \infty & 10\\ 11 & 9 & \infty & 0 & 7\\ 9 & 8 & 10 & 7 & 0\end{bmatrix}[/tex]

The matrix on the left above corresponds to the weighted graph on the right.

Using the [tex]\text{Kruskal's algorithm}[/tex] we can select the cheapest edge that is not creating a cycle.

Starting with 2 edges of weight 3 and the edge of weight 5 is forbidden but the edge is 7  is available.

The edge of the weight 8 completes a minimum spanning tree and total weight 21.

If the edge of weight 8 had weight 10 then either of the edges of weight 9 could be chosen the complete the tree and in this case there could be 2 spanning trees with minimum value.

A population of bacteria contains 80 bacteria in generation 1 and triples in
population every generation. This sequence represents the number of
bacteria for the first few generations:
80, 240, 720, ...
What is the explicit formula for the number of bacteria in generation n?
A. a(n) = 80 + (n - 1)3
B. a(n) = 3.801-1
C. a(n) = 3 + (n-1)80
D. a(n) = 80.30-1

Answers

Answer:

A

Step-by-step explanation:

Answer:a(n)=80•3n-1

Step-by-step explanation:

Is interquartile range a measure of center or a measure of variation?

Answers

Answer:

The interquartile range is the middle half of the data that is in between the upper and lower quartiles. ... The interquartile range is a robust measure of variability in a similar manner that the median is a robust measure of central tendency.

please help, will give brainliest!!

Answers

Answer:

3

Step-by-step explanation:

[tex] \frac{3x - 3}{x} \div \frac{x - 1}{x} [/tex]

[tex] \frac{3(x - 1)}{x} \times \frac{x}{x - 1} = 3[/tex]

The graph below shows two polynomial functions, f(x) and g(x): Graph of f of x equals x squared minus 2 x plus 1. Graph of g of x equals x cubed plus 1 Which of the following statements is true about the graph above? (4 points) g(x) is an even degree polynomial with a positive leading coefficient. g(x) is an odd degree polynomial with a negative leading coefficient. f(x) is an even degree polynomial with a positive leading coefficient. f(x) is an odd degree polynomial with a negative leading coefficient.

Answers

9514 1404 393

Answer:

  (c)  f(x) is an even degree polynomial with a positive leading coefficient.

Step-by-step explanation:

The leading terms of the two functions are ...

  f(x): x² (even degree, positive coefficient: 1)

  g(x): x³ (odd degree, positive coefficient: 1)

Then it is true that ...

  f(x) is an even degree polynomial with a positive leading coefficient

Suppose the distributor charges the artist a $40.00 cost for distribution, and the streaming services pays $4.00 per unit. (Note: One unit = one thousand streams)

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

Formula: y = 40x + 4 (Graph Attached)

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

After how many streams will you pay for the distributor charges? (Hint: this is where the line crosses the x-axis, round to the nearest thousand)

Answers

Answer:

356 streams

Step-by-step explanation:

From the graph, you will see that the line cross the x-axis at x = 8.8

Substitute into the expression y = 40x + 4

y = 40(8.8)+4

y = 352 + 4

y = 356

Hence the distributor charges will be paid for after 356 streams

Please help explanation if possible

Answers

Answer:

Step-by-step explanation:

so d = 2r which means r = 5cm.

A = πr^2 = π(5)^2 = 25π =  (25)(3.14) = 78.5 cm^2.

So input 78.5

Answer:

see below

Step-by-step explanation:

so d = 2r which means r = 5cm.

A = πr^2 = π(5)^2 = 25π =  (25)(3.14) = 78.5 cm^2.

So input 78.5

HOPE IT HELPS YOU

7. A machine produces memory sticks of varying lengths, distributed uniformly between 3mm and 13 mm. Memory sticks longer than 10 mm do not meet the design criteria and must be scrapped. Calculate the proportion of memory sticks that will be scrapped, which is the probability that memory stickers longer than 10 mm will be scrapped.

Answers

Answer:

The proportion of memory sticks that will be scrapped is 0.3 = 30%.

Step-by-step explanation:

Uniform probability distribution:

An uniform distribution has two bounds, a and b.  

The probability of finding a value of at lower than x is:

[tex]P(X < x) = \frac{x - a}{b - a}[/tex]

The probability of finding a value between c and d is:

[tex]P(c \leq X \leq d) = \frac{d - c}{b - a}[/tex]

The probability of finding a value above x is:

[tex]P(X > x) = \frac{b - x}{b - a}[/tex]

Distributed uniformly between 3mm and 13 mm.

This means that [tex]a = 3, b = 13[/tex]

Calculate the proportion of memory sticks that will be scrapped:

[tex]P(X > 10) = \frac{13 - 10}{13 - 3} = \frac{3}{10} = 0.3[/tex]

The proportion of memory sticks that will be scrapped is 0.3 = 30%.

PLS HELP I DONT KNOW THIS ONE

Answers

Answer:

x+3

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

(x-3)(x-2)(x-4)

Step-by-step explanation:

x+4             x^2 -16

---------------÷ -------------

x^2 - 5x+6     x+3

Copy dot flip

x+4                x+3

--------------- * -------------

x^2 - 5x+6     x^2 -16

Factor

x+4                x+3

--------------- * -------------

(x-3)(x-2)     (x-4)(x+4)

Cancel like terms

1                   x+3

--------------- * -------------

(x-3)(x-2)     (x-4)1

x+3

---------------   x cannot equal 3,2,4 -4

(x-3)(x-2)(x-4)

Christian randomly selects students from his grade to rate a math test as easy, moderate, or difficult. Of the students he surveyed, 13 said the test was easy, 11 rated it as moderate, and 3 found it difficult. Assuming that all students took the same test, how many of the 162 total students in Christian’s grade would probably rate the test something other than easy?
A.
27
B.
78
C.
84
D.
126

Answers

Answer:

C.

84

Step-by-step explanation:

This question is solved using proportions.

From the sample:

11 + 3 = 14 out of 13 + 11 + 3 = 27 would rate the test something other than easy.

Out of 162:

Applying the rule of three:

14 - 27

x - 162

Applying cross multiplication:

[tex]27x = 14*162[/tex]

[tex]x = \frac{14*162}{27}[/tex]

[tex]x = 84[/tex]

Thus the correct answer is given by option C.

Answer:

I hope this helps

Step-by-step explanation:

What is the approximate value of log b to the nearest hundredth? 0.93 1.23 9.16 65.53

Answers

Answer:

1.23

Step-by-step explanation:

strontium-90 is a radioactive material that decays according to the function A(t)=A0e−0.0244t, where A0 is the initial amount present and A is the amount present at time t​ (in years). Assume that a scientist has a sample of 400 grams of​ strontium-90. ​
(a) What is the decay rate of​ strontium-90?
​(b) How much​ strontium-90 is left after 30 ​years?
​(c) When will only 100 grams of​ strontium-90 be​ left?
​(d) What is the​ half-life of​ strontium-90?

​(a) The decay rate of​ strontium-90 is nothing​%.
​(Type an integer or a decimal. Include the negative sign for the decay​ rate.)

Answers

Answer:

Step-by-step explanation:

The decay rate of strontium-90 is -.0244 as given.

For b., we have to use the formula to find out how much is left after 30 years. This will be important for part d.

[tex]A(t)=400e^{-.0244(30)}[/tex] which simplifies a bit to

A(t) = 400(.4809461353) so

A(t) = 192.4 g

For c., we have to find out how long it takes for the initial amount of 400 g to decay to 100:

[tex]100=400e^{-.0244t}[/tex]. Begin by dividing both sides by 400:

[tex].25=e^{-.0244t[/tex] and then take the natural log of both sides:

[tex]ln(.25)=lne^{-.0244t[/tex] . The natural log and the e cancel each other out since they are inverses of one another, leaving us with:

ln(.25) = -.0244t and divide by -.0244:

61.8 years = t

For d., we figured in b that after 30 years, 192.4 g of the element was left, so we can use that to solve for the half-life in a different formula:

[tex]A(t)=A_0(.5)^{\frac{t}{H}[/tex] and we are solving for H. Filling in:

[tex]192.4=400(.5)^{\frac{30}{H}[/tex] and begin by dividing both sides by 400:

[tex].481=(.5)^{\frac{30}{H}[/tex] and take the natural log of both sides, which allows us to pull the exponent out front. I'm going to include that step in with this one:

ln(.481) = [tex]\frac{30}{H}[/tex] ln(.5) and then divide both sides by ln(.5):

[tex]\frac{ln(.481)}{ln(.5)}=\frac{30}{H}[/tex] and cross multiply and isolate the H to get:

[tex]H=\frac{30ln(.5)}{ln(.481)}[/tex] and

H = 28.4 years

simplify 7-(3n+6)+10n​

Answers

Answer:

1 + 7n

Step-by-step explanation:

7-(3n+6)+10n​

7 - 3n - 6 + 10 n

1 - 7n

Answered by Gauthmath

Find y on this triangle

Answers

Answer:

5√3 / 2

Step-by-step explanation:

tan 30 = ( 5 / 2 ) / y

1 / √3 = 5 / 2y

2y = 5√3

y = 5√3 / 2

Write an algebraic expression for each person’s share, if P people share 16 slices of pizza equally.

Answers

Answer:

P /16

Step-by-step explanation:

Take the total amount, P and divide by the number of people sharing, 16

P /16

Use the equation d=z–9 to find the value of d when z=10.

d=

Answers

Step-by-step explanation:

d = z - 9

d = 10 - 9  ----> substitute

d = 1

6. 5x = -25
a. X= 5
b. X=-5
c. x=2

Answers

Answer:

x = -5

Step-by-step explanation:

5x = -25

Divide each side by 5

5x/5 = -25/5

x = -5

Answer:

[tex]Option\ B,\ x = -5[/tex]

Step-by-step explanation:

Step 1:  Divide both sides by 5

[tex]5x = -25[/tex]

[tex]5x / 5 = -25 / 5[/tex]

[tex]x = -25/5[/tex]

[tex]x = -5[/tex]

Answer:  [tex]Option\ B,\ x = -5[/tex]

perimeter of a circle 8 centimeter wide

Answers

C=2•3.14•4 is the formula which equals 25.13

Answer:

25.13 cm

Step-by-step explanation:

Perimeter ( circumference ) of a circle = 2πr

Given,

The circle is 8 cm wide

which means,

The diameter (d) of the circle is 8 cm.

Radius (r) of the circle = d/2

= 8/2

= 4

Radius = 4 cm

Putting the value in the formula;

2πr

= 2 (22/7) (4)

= 25.13 cm (approx)

One angle of an isosceles triangle is 16 what are the other 2 angles

Answers

Answer:

other two angle will be

82

as 82+82+16 = 180'

1. You are given the 3rd and 5th term of an arithmetic sequence. Describe in words how to determine the general term.

2. You are given the 3rd and 5th term of an geometric sequence. Describe how to determine the 10th term without finding the general term.

Answers

Step-by-step explanation:

1. In an arithmetic sequence, the general term can be written as

xₙ = y + d(a-1), where xₐ represents the ath term, y is the first value, and d is the common difference.

Given the third term and the fifth term, and knowing that the difference between each term is d, we can say that the 4th term is x₃+d and the fifth term is the fourth term plus d, or (x₃+d)+d =

x₃+2d. =x₅ Given x₃ and x₅, we can subtract x₃ from both sides to get

x₅-x₃ = 2d

divide by 2 to isolate d

(x₅-x₃)/2 = d

This lets us solve for d. Given d, we can say that

x₃ = y+d(2)

subtract 2*d from both sides to isolate the y

x₃ -2*d = y

Therefore, because we know x₃ and d at this point, we can solve for y, letting us plug y and d into our original equation of

xₙ = y + d(a-1)

2.

Given the third and fifth term, with a common ratio of r, we can say that the fourth term is x₃ * r. Then, the fifth term is

x₃* r * r

= x₃*r² = x₅

divide both sides by x₃ to isolate the r²

x₅/x₃ = r²

square root both sides

√(x₅/x₃) = ±r

One thing that is important to note is that we don't know whether r is positive or negative. For example, if x₃ = 4 and x₅ = 16, regardless of whether r is equal to 2 or -2, 4*r² = 16. I will be assuming that r is positive for this question.

Given the common ratio, we can find x₆ as x₅ * r, x₇ as x₅*r², and all the way up to x₁₀ = x₅*r⁵. We don't know the general term, but can still find the tenth term of the sequence

Please help !!! Plzzzz

Answers

Answer:  7

Explanation:

Because we have a midsegment, this means that it is half as long as the side it's parallel to. You can think of "mid" as "middle" and that could lead to "halfway" to remember to take half.

So z = 14/2 = 7

I want to know how to solve this equation

Answers

Answer:

B

Step-by-step explanation:

5³.5^×

simply means

5³×5^×

using indices rule,

multiplication is addition

5 is common

so 5(³+×)

hence 5^3+×

Suppose a deck of cards contains 13 cards:
5 green cards numbered 1-5, 4 red cards numbered 1-4, and 4 blue cards numbered 1-4.
For 3.1-3.3, 5 draws are made without replacement. X is the number of green cards drawn and Y is the number of red cards drawn. Z is the sum of the numbers on the tickets.
G1 = first card is green
G2 = second card is green
Enter the probability as a fraction.
P(at least one green) = ______.

Answers

Answer:

[tex]P(G_1) = \frac{5}{13}[/tex]

[tex]P(G_2) = \frac{1}{3}[/tex]

[tex]P(X \ge 1) = \frac{25}{39}[/tex]

Step-by-step explanation:

Given

[tex]G = 5[/tex]

[tex]R = 4[/tex]

[tex]B = 4[/tex]

[tex]n = 13[/tex]

Solving (a): [tex]P(G_1)[/tex]

This is calculated as:

[tex]P(G_1) = \frac{G}{n}[/tex]

[tex]P(G_1) = \frac{5}{13}[/tex]

Solving (b): [tex]P(G_2)[/tex]

This is calculated as:

[tex]P(G_2) = \frac{G - 1}{n - 1}[/tex] -- this is so because the selection is without replacement

[tex]P(G_2) = \frac{5 - 1}{13 - 1}[/tex]

[tex]P(G_2) = \frac{4}{12}[/tex]

[tex]P(G_2) = \frac{1}{3}[/tex]

Solving (c): [tex]P(X \ge 1)[/tex]

Using the complement rule, we have:

[tex]P(X \ge 1) = 1 - P(X = 0)[/tex]

To calculate [tex]P(X = 0)[/tex], we have:

[tex]G = 5[/tex] --- Green

[tex]G' = 8[/tex] ---- Not green

The probability that both selections are not green is:

[tex]P(X = 0) = P(G'_1) * P(G'_2)[/tex]

So, we have:

[tex]P(X = 0) = \frac{G'}{n} * \frac{G'-1}{n-1}[/tex]

[tex]P(X = 0) = \frac{8}{13} * \frac{8-1}{13-1}[/tex]

[tex]P(X = 0) = \frac{8}{13} * \frac{7}{12}[/tex]

Simplify

[tex]P(X = 0) = \frac{2}{13} * \frac{7}{3}[/tex]

[tex]P(X = 0) = \frac{14}{39}[/tex]

Recall that:

[tex]P(X \ge 1) = 1 - P(X = 0)[/tex]

[tex]P(X \ge 1) = 1 - \frac{14}{39}[/tex]

Take LCM

[tex]P(X \ge 1) = \frac{39 -14}{39}[/tex]

[tex]P(X \ge 1) = \frac{25}{39}[/tex]

On a map, the scale shown is 1 inch : 5 miles. If an island is 2.5 squire inches on the map, what is the actual area of the island? The actual island's area is square miles.​

Answers

Answer:

62.5 square miles

Step-by-step explanation:

if the scale is 1 in. = 5 mi, then 1 square in. = 25 square miles

so if 1 in^2 = 25 mi^2

then you make a proportion

25/1 = x/2.5

(the square inches on the bottom and the square miles on top)

solving for x gives you

x=62.5 square miles

Find the missing side length in the image below

Answers

find the area and volume of the trapezoids first

A manufacturer of potato chips would like to know whether its bag filling machine works correctly at the 409 gram setting. It is believed that the machine is underfilling the bags. A 21 bag sample had a mean of 401 grams with a standard deviation of 26. A level of significance of 0.1 will be used. Assume the population distribution is approximately normal. Determine the decision rule for rejecting the null hypothesis. Round your answer to three decimal places.

Answers

Answer:

The decision rule is to Reject H0 if Z ≤ -1.282

Step-by-step explanation:

We are given;

Population mean; μ = 409 g

Sample mean; x¯ = 401 g

Sample size; n = 21

Standard deviation; s = 26

Let's define the hypotheses;

Null hypothesis; H0: μ = 409 g

Alternative hypothesis; Ha : μ ≠ 409 g

Formula for test statistic is;

z = (x¯ - μ)/(s/√n)

z = (401 - 409)/(26/√21)

z = -1.410

z-value is negative and thus this is a lower tail test.

At significance level of 0.1, the critical value is -1.282.

Thus, the decision rule is;

Reject H0 if Z ≤ -1.282

If 25 burgers feed 15 kids how many burgers would feed 55 kids

Answers

Answer:

1375

Step-by-step explanation:

muscle max gym charges a $30 fee to join plus $2 each day that you go workout. Capital cross-fit charges $10 to join and $4 each day you use the gym. After how many days of workouts would the two gyms have cost you the same amount of money?

Answers

Set up equations for each gym.

multiply daily cost by number of days(x) and add the fee:

Muscle max: 2x + 30

Capital: 4x + 10

Now set them

Equal to each other and solve for x:

2x + 30 = 4x + 10

Subtract 2x from both sides :

30 = 2x + 10

Subtract 10 from both sides :

20 = 2x

Divide both sides by 2:

X = 10

It will take 10 days

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