You are enrolling swimmers in a study on lung capacity. You want 25% of your sample to be those who compete at 100m or less distances and 50% to be swimmers who compete at 100m-500m distances and 25% to be swimmers who compete at >500m distances. You begin enrolling for your study at 5am at the pool. By 9 AM you have all of your 100-500m swimmers enrolled, and all of your >500m swimmers enrolled. This is an example of what type of sampling method

Answers

Answer 1

Answer:

Stratified sampling

Step-by-step explanation:

Samples may be classified as:

Convenient: Sample drawn from a conveniently available pool.

Random: Basically, put all the options into a hat and drawn some of them.

Systematic: Every kth element is taken. For example, you want to survey something on the street, you interview every 5th person, for example.

Cluster: Divides population into groups, called clusters, and each element in the cluster is surveyed.

Stratified: Also divides the population into groups. However, then only some elements of the group are surveyed.

In this question:

People divided by groups, for each group(<100, >100<500, >500), a number(not all) is selected, so stratified sampling.


Related Questions

what is the area of the triangle ://

Answers

Answer:

The area of a triangle is:

Area = 1/2(bh)

Area = 1/2(70)

Area = 35 square inches

Let me know  if this helps!

Answer:

A = 35

Step-by-step explanation:

a^2 + b^2 = c^2

10^2 + b^2 = 12^2

100 + b^2 = 144

144 - 100 = b^2

b^2 = 44

b = 6.6

6.6 x 10 = 66/2 = 33

7 - 6.6 = 0.4

10 x 0.4 = 4/2 = 2

Area = 33 + 2

Area = 35

the length of a rectangle is 4 meters longer than the width. if the area is 22 square meters , find the rectangle dimension

Answers

Let breadth be x

Length=x+4

We know

[tex]\boxed{\sf Area_{(Rectangle)}=Length\times Breadth}[/tex]

[tex]\\ \sf\longmapsto x(x+4)=22[/tex]

[tex]\\ \sf\longmapsto x^2+4x=22[/tex]

[tex]\\ \sf\longmapsto x^2+4x-22=0[/tex]

By solving

[tex]\\ \sf\longmapsto x=-2\pm\sqrt{26}[/tex]

It doesnot have any real roots

The sum of 'n' terms of an arithmetic sequence is 4n^2+3n. What is the first term, the common difference, and the sequence?

Answers

Answer:

d=8 and a=7

Step-by-step explanation:

The sum of a arithmetic sequence is given by (n/2)*(2a+(n-1)d). Comparing coefficients with the given Sn, we have; a-d/2=3 and d/2=4, d=8 and a=7. The sequence is 7, 15, 23, 31, 39

Identify the similar triangle. Then find each measure (round to the nearest tenth).

Answers

Answer:

ZWU ~ WYU

WY = 2.5

UY= 1.5

Step-by-step explanation:

ZUW ~ WUY ~ ZWY

5/3=x+1/x

Cross multiply

5x=3x+3

2x=3

x=3/2 OR 1.5

please help this is due soon

Answers

For the A parts just make all the second numbers negative example: if it were 5,1 make it (5,-1) and for the B part make all the first numbers a negative example: if it were 5,1 make it (-5,1)

The figure shows an equilateral triangle with its sides as indicated. find the length of each side of the triangle .

I Will Mark Brainliest​

Answers

Answer:

21

Step-by-step explanation:

All three sides are equal

2x-7 = x+y-9 = y+5

Using the last two

x+y-9 = y+5

Subtract y from each side

x+y-9-y = y+5-y

x-9 = 5

Add 9 to each side

x -9+9 = 5+9

x=14

We know the side length is

2x-7

2(14) -7

28-7

21

The side length is 21

What year was it when I was a freshman if I graduated this year(2021)?

Answers

Answer:

2019

Step-by-step explanation:

I am assuming you mean graduated from high school. If that's the case it's 2019. Sophmore year means 9th grade. which is 2019!

There is 3m wide path around a circular cricket ground having the diameter of 137 m. Find the area of the path.​

Answers

Answer:

1320 m^2

Step-by-step explanation:

area of ground = π r ^2

= (22/7) × (137/2)^2

= 14,747.0714286 m^2

area of ground and path

=( 22/7)(143/2)^2

= 16,067.0714286 m^2

area of path

=16,067.0714286 -14,747.0714286

= 1320 m^2

note :

r = radius = diameter /2

area of a circle = π r^2

diameter of circle created with path and ground = 137 + 2 × width of path

= 137 + 2× 3 = 143 m

Current
How many years will it take for an initial investment of $60,000 to grow to $90,000? Assume a rate of interest of
4% compounded continuously.

>It will take about _years for the investment to grow to $90,000.
(Round to two decimal places as needed.)

Answers

Answer:

I think i don't know the answer i am so sorry!!!

maybe someone else can Answer

6+7=10
13+8=18
32+21=32
11+34=0
31+03=?​
process please

Answers

Answer:

6+7=13

13+8=21

32+21=52

11+34=46

31+03=34

Step-by-step explanation:

im not sure in the 31+03

The height of the triangle is 4 meters longer than twice its base. find the height if the area of the triangle is 80 square meters. The height must be ___meters​

Answers

Answer:

The height is 20 meters

Step-by-step explanation:

First set up the equation (Area)80=bh/2 then set up another equation, (height) h=4+2b (base). After this you can substitute h in the equation to end up with 80=(b(2b+4))/2 simplify it to get 80=b^2+2b then solve. The base is 8 meters, plug into the formula that we made before and you find the height is 20 meters.

The height is 20 meters

2. Solve the following:
a. When six is added to four times a number the result is 50. Find the number.
b. The sum of a number and nine is multiplied by -2 and the answer is -8. Find the
number
10
m in​

Answers

Step-by-step explanation:

a) let number=x

four times a number=4x

Condition:

4x+6=50

4x=50-6

4x=44

x=44/4

x=11

b) Condition:

x+9×-2=-8

x-18=-8

x=-8+18

x=10

Note:if you need to ask any question please let me know.

Find the slope of the line tangent to the graph of x²+2xy² +3y=31 at the point (2, -3)​

Answers

9514 1404 393

Answer:

  22/21

Step-by-step explanation:

Taking the derivative, we have ...

  2x·dx +2y²·dx +4xy·dy +3·dy = 0

  dx(2x +2y²) +dy(4xy+3) = 0

At the given point, this is ...

  dx(2·2 +2·(-3)²) +dy(4·2·(-3) +3) = 0

  22dx -21dy = 0

  dy/dx = 22/21

The slope of the tangent at the point of interest is 22/21.

If a point in quadrant IV is reflected in the y-axis, its image will lie in quadrant:
A. IV
B. II
C. I
D. III

Answers

Answer:

Option D is correct.

Step-by-step explanation:

A plane mirror shows that the image formed by it is of same size as that of object, same distance as that of object and same orientation and laterally inverted.

So, when a point is in IV quadrant and reflection is from Y axis, the image is in  III quadrant.  

Find the area of the shape shown below.

Answers

Answer:

28 units²

Step-by-step explanation:

Area of trapezoid =

2(8 + 4)/2 = 12

Area of rectangle =

2 x 8 = 16

16 + 12 = 28

If my answer is incorrect, pls correct me!

If you like my answer and explanation, mark me as brainliest!

-Chetan K

A turboprop plane flying with the wind flew 1,200 mi in 4 h. Flying against the wind, the plane required 5 h to travel the same distance. Find the rate of the wind and the rate of the plane in calm air.

Answers

Answer:

30 and 270 respectively

Step-by-step explanation:

Let the speed of plane in still air be x and the speed of wind be y.

ATQ, (x+y)*4=1200 and (x-y)*5=1200. Solving it, we get x=270 and y=30


Which description matches the function represented by the values in this
table?
X х
у
14
1
2
56
224
4
896
5
3584
O A. exponential decay
OB. linear growth
O C. linear decay
D. exponential growth

Answers

The given table represents Exponential growth.

Exponential growth:

The process of Quantity rising over time is called exponential growth. An exponential function is used to create an exponential growth curve, which represents a pattern of data that shows a rise over time. Where the Exponential decay helps to understand the rapid decrease in a period of time

Here we have

The table

х     1       2       3       4          5  

у    14     56    224    896    3584  

From the given table, we can observe that

[tex]\frac{14}{56} = \frac{56}{224} = \frac{896}{3584} = \frac{1}{4}[/tex]    

Since the absolute value of the common ratio is less than 1 i.e 1/4

And the values are increasing

Therefore,

The given table represents Exponential growth.

Learn more about Exponential growth at

https://brainly.com/question/8706992

#SPJ1

7. Solve for x: x/6 - y/3 = 1

Please give steps!

Answers

x/6 - y/3 = 1
<=> x/6 = 1+ y/3
<=> x/6 = (3+y)/3
<=> x = (3+y)/3 x 6
<=> x = 2(3+y)
So the answer is x = 2(3+y)

What is the sum of the infinite geometric series?​

Answers

Answer:

-6

Step-by-step explanation:

a1= -3

r= -(3/2)/-3 = 0.5

r>-3

s= a1/1-r

= -3/1-0.5

=-6

Question 17 of 25
Solve the inequality. Enter the answer as an inequality that shows the value of
the variable; for example f>7, or 6 < w. Where necessary, use <= to write s
and use >= to write .
V-(-5) <-9
Answer here
I
SUBMIT

Answers

Answer:

v-(-5)<-9

v- remove brackets -5

v- -5= -4 +5 ( opposite operation)

v- = -4

v< -4

I need the help ASAP please

Answers

Answer:

Option B

Answered by GAUTHMATH

Triangle DEF contains right angle E. If angle D measures 40° and its adjacent side measures 7.6 units, what is the measure of side EF? Round your answer to the nearest hundredth.

Answers

[tex]\\ \rm\longmapsto cot40=\dfrac{7.6}{EF}[/tex]

[tex]\\ \rm\longmapsto EF=\dfrac{7.6}{cot40}[/tex]

[tex]\\ \rm\longmapsto EF=\dfrac{7.6}{1.19}[/tex]

[tex]\\ \rm\longmapsto EF=6.38units[/tex]

Answer:

[tex]\displaystyle 6,38\:units[/tex]

Step-by-step explanation:

You would set your proportion up like so:

[tex]\displaystyle \frac{7,6}{EF} = cot\:40° \\ \\ 7,6 = EFcot\:40° → 6,3771571969... = \frac{7,6}{cot\:40°} \\ \\ 6,38 ≈ EF[/tex]

I am joyous to assist you at any time.

WORTH 15 POINTSSSSSSSSS

Answers

Answer:

15

Step-by-step explanation:

Difference in distances = 75-60 = 15 miles

So Car A travels 15 miles more than Car A in an hour

Answered by Gauthmath

Here's the result of this question
The point (-2,7) has undergone the following transformations:
1. Translated 1 unit up and 4 units left
Then
2. Reflected about the c-axis
Then
3. Rotated 90° anticlockwise about the origin

A) Its final coordinates are (3,-1)
B) Its final coordinates are (8,-6)
C) Its final coordinates are (-8,6)
D) Its final coordinates are (-3,1)

Answers

Answer:

B) Its final coordinates are (8,-6)

Step-by-step explanation:

1. Translated 1 unit up and 4 units left

(-2,7) becomes (-6, 8)

2. Reflected about the x-axis

(-6,8) becomes (-6, -8)

3. Rotated 90° anticlockwise about the origin

(-6, -8) becomes (8, -6) because when rotating 90 degrees anticlockwise about the origin, point A (x,y) becomes point A' (-y,x). In other words, switch the x and y and make y negative.

Coefficient and degree of the polynomial

Answers

Answer:

The leading coefficient is -8 as it is a mix of x and cardinal, if it was x alone then it wouldn't be the coefficient, we would use the next number shown.

If it was just a number and no x then it would still be the coefficient.

The degree is 9 as it is the highest power shown.

Step-by-step explanation:

See attachment for examples

HURRY PLEASE!!!!!!
Line AB has a slop of 1/2
What would the slope of line CD have to be if we knew CD was perpendicular to AB?
2
-2
1/2
-1/2

Answers

Answer:

-2

Step-by-step explanation:

Perpendicular lines have slopes that are negative reciprocals

Take the slope of AB = 1/2

-1/(1/2)

-1 * 2/1

-2

The slope of a line perpendicular is -2

please help I have 3 mins left

Answers

Answer:

the first one is 3.7 x 10^-4

and the second one is 3.7 x 10^4

explanation:

when we have decimals we are going backward,

therefore "0.00037" would be a negative number

to find the scientific notation form, we have to move the decimal over to the left untill we get 3.7

it took 4 moves to the right to get to 3.7, and since were dealing with decimals it will be negative,

so the first one is 3.7 x 10^4

the second one however is not a decimal so it will be a positive exponent.

now remember that there is always a decimal after a number we might just not see it.

so, going from the very end of the number it takes us 4 moves to the left to get to 3.7

so,

the second one will be 3.7 x 10^4

hope this helped :)

Driving 70 mph, it takes Alicia 3 hours to reach the airport to go on a vacation. It then takes her 3 hours to get to her destination with the jet traveling at a speed of 400 mph. How many miles does Alicia travel to get to her destination?

Answers

Answer:

Total distance covered= 910 miles

Step-by-step explanation:

Distance = speed x time

Distance covered from home to airport = 70 x 3= 210 miles

Distance covered from airport to destination= 350 x 2= 700 miles

Add them together to get the final answer.

A cylinder has a radius of 6 inches and is 15 inches tall what is the volume of the cylinder round to the nearest whole square inch

Answers

Answer:

V=TT r²h

Step-by-step explanation:

TT=3.14

r=6

h=15

V=TTr²h

V=3.14×6²×15

V=3.14×36×15

V=1695.6inch³

A small airplane flies 750 miles with an average speed of 250 miles per hour. 1.75 hours after the plane leaves, a Boeing 747 leaves from the same point. Both planes arrive at the same time; what was the average speed of the 747?

Answers

Answer:

The average speed of the 747 was of 600 miles per hour.

Step-by-step explanation:

A small airplane flies 750 miles with an average speed of 250 miles per hour.

Velocity is distance divided by time, and here, we find the time of the small airplane. So

[tex]v = \frac{d}{t}[/tex]

[tex]250 = \frac{750}{t}[/tex]

[tex]250t = 750[/tex]

[tex]t = \frac{750}{250}[/tex]

[tex]t = 3[/tex]

1.75 hours after the plane leaves, a Boeing 747 leaves from the same point. Both planes arrive at the same time;

This means that it traveled 750 miles in 3 - 1.75 = 1.25 hours.

What was the average speed of the 747?

[tex]v = \frac{d}{t} = \frac{750}{1.25} = 600[/tex]

The average speed of the 747 was of 600 miles per hour.

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