A physical therapist wants to determine the difference in the proportion of men and women who participate in regular sustained physical activity. What sample size should be obtained the wishes the estimate to be within three percentage points
with 90% confidence, assuming that
(a) he uses the estimates of 21.3% male and 19.5% female from a previous year?
(b) he does not use any prior estimates?
(a)n (Round up to the nearest whole number)
(b) (Round up to the nearest whole number.)

Answers

Answer 1

Using the z-distribution and the formula for the margin of error, it is found that:

a) A sample size of 54 is needed.

b) A sample size of 752 is needed.

In a sample with a number n of people surveyed with a probability of a success of [tex]\pi[/tex], and a confidence level of [tex]\alpha[/tex], we have the following confidence interval of proportions.

[tex]\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]

In which z is the z-score that has a p-value of [tex]\frac{1+\alpha}{2}[/tex].

The margin of error is of:

[tex]M = z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]

90% confidence level, hence[tex]\alpha = 0.9[/tex], z is the value of Z that has a p-value of [tex]\frac{1+0.9}{2} = 0.95[/tex], so [tex]z = 1.645[/tex].

Item a:

The estimate is [tex]\pi = 0.213 - 0.195 = 0.018[/tex].

The sample size is n for which M = 0.03, hence:

[tex]M = z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]

[tex]0.03 = 1.645\sqrt{\frac{0.018(0.982)}{n}}[/tex]

[tex]0.03\sqrt{n} = 1.645\sqrt{0.018(0.982)}[/tex]

[tex]\sqrt{n} = \frac{1.645\sqrt{0.018(0.982)}}{0.03}[/tex]

[tex](\sqrt{n})^2 = \left(\frac{1.645\sqrt{0.018(0.982)}}{0.03}\right)^2[/tex]

[tex]n = 53.1[/tex]

Rounding up, a sample size of 54 is needed.

Item b:

No prior estimate, hence [tex]\pi = 0.05[/tex]

[tex]M = z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]

[tex]0.03 = 1.645\sqrt{\frac{0.5(0.5)}{n}}[/tex]

[tex]0.03\sqrt{n} = 1.645\sqrt{0.5(0.5)}[/tex]

[tex]\sqrt{n} = \frac{1.645\sqrt{0.5(0.5)}}{0.03}[/tex]

[tex](\sqrt{n})^2 = \left(\frac{1.645\sqrt{0.5(0.5)}}{0.03}\right)^2[/tex]

[tex]n = 751.7[/tex]

Rounding up, a sample of 752 should be taken.

A similar problem is given at https://brainly.com/question/25694087


Related Questions

what is the greatest number of obtuse angles that a right triangle can contain

Answers

Step-by-step explanation:

i think this is the answer

Answer:

Zero

Step-by-step explanation:

Obtuse angle is the angle greater than 90°.

A right triangle has one 90° and the sum of remaining angles is 90°.

It means a right triangle can't have an obtuse angle.

Write 5 • 5 • 5 • 5 • 5 • 5 • 5 using an exponent.

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Answer:

5^6

Step-by-step explanation:

5 was multiplied repeatedly 6 times, so it's 5 to the power of 6

Answer:

5 to the power of 6 or 5^6

Step-by-step explanation:

this cubiod is made from 6 small cubes write how many small cubes there are in this cubiod
Pleas help ​

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Answer:

16 I guess.

Step-by-step explanation:

lolololololol?

If a slingshot is used to shoot a marble straight up into the air from 2 meters above the
ground with an initial velocity of 30 meters per second, for what values of time t will the
marble be over 35 meters above the ground? (Refer to Exercise 25 in Section 2.3 for assistance
if needed.) Round your answers to two decimal places

Answers

Answer:

use this equation: GPE=mgh

Step-by-step explanation:

GPE = gravitational potential energy = J

m = mass = Kg

g = gravitational field = N/kg = world's gravitational field is 9.8N/kg

h = height = m

The graph of the linear function is shown on the coordinate grid. What is the equation of this line?​

Answers

y=-1/3-2

Hope this helps!! :)

Study the visual fraction below.

Answers

Answer:

The answer would be D

Step-by-step explanation:

5 1/3 ÷ 2/3 = 8

16/3 ÷ 2/3 = 8

16 ÷2 = 8

-4/5 divided by 1/3
Please asap

Answers

the straight up answer is -12/5

Can someone help? anyone?

Answers

Answer:

The right answer is letter C.

Step-by-step explanation:

I hope it's help

have a nice day and night

Central/Inscribed angles w work pls i beg last one

Answers

Answer:  346/45

=======================================================

Explanation:

Let point A be the center of the circle.

The inscribed angle CED doubles to the central angle CAD due to the inscribed angle theorem.

angle CAD = 2*(angle CED)

angle CAD = 2*(7x+6)

angle CAD = 14x+12

Angle CAD is the same as minor arc CD. These are two different ways to describe the same thing more or less. This is because the central angle subtends or cuts off the minor arc CD.

-----------

The three arc pieces CE, ED and CD all combine to form a 360 degree circle.

(arc CE) + (arc ED) + (arc CD) = 360

(18x+1) + (13x+1) + (14x+12) = 360

(18x+13x+14x) + (1+1+12) = 360

45x+14 = 360

45x = 360-14

45x = 346

x = 346/45

This approximates to roughly x = 7.6889, but I have a feeling your teacher will want the fraction form.

Xy3-9xyz2 is my math problem and I need help with the complete breakdown

Answers

(x • (y³)) - 32xyz²

Pull out like factors :

xy³ - 9xyz² = xy • (y² - 9z²)

Factoring: y² - 9z²

Theory : A difference of two perfect squares, A2 - B2 can be factored into (A+B) • (A-B)

Proof : (A+B) • (A-B) =

A² - AB + BA - B² =

A² - AB + AB - B² =

A² - B²

Note : AB = BA is the commutative property of multiplication.

Note : - AB + AB equals zero and is therefore eliminated from the expression.

Check : 9 is the square of 3

Check : y² is the square of y¹

Check : z² is the square of z¹

Factorization is : (y + 3z) • (y - 3z)

Final result :

xy • (y + 3z) • (y - 3z)

4. Simplify: -3(2x - 5)-2(4x+3)
A.14x-9
B.-2x+21
C.-14x+9
D.-14x+ 21



Can someone help me ?

Answers

your answer will be c. -14x+9
the answer is C. -14x+9


distribute numbers outside parentheses then combine like terms.

Simplify.

5x+3(x+2)+3

A. 8x + 9
B. 5x + 8
C. 8x + 5
D. 6x + 8

Answers

Answer:

A- 8x+9

Step-by-step explanation:

Answer: A) 8x + 9

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

5x + 3 (x + 2) + 3

5x + 3x + 6 + 3

8x + 6 + 3

8x + 9

<3

What is the value of v?

Answers

By isosceles triangle theorem,

Angle ZXY = Angle ZYX

The sum of the angles in a triangle is 180 degrees.

106 + 2 same angles (-106) = 180 (-106)  (Subtract 106 by both sides)

2 same angles (/ 2) = 74 (/ 2)   (Divide 2 by both sides)

V = 37

Answer:

The value of v is 37°.

Step-by-step explanation:

Given that △ XYZ is an isosceles triangle where both sides have the equal angles. The total angle of △ is 180°. Let ∠ZXY and ∠ZYX be the same angles:

Let ∠ZXY = v, ∠ZYX = v, ∠ XZY = 106°,

∠ZXY + ∠ZYX + ∠XZY = 180°

v + v + 106° = 180°

2v + 106° = 180°

2v = 180° - 106°

2v = 74°

v = 74 ÷ 2

v = 37°

Given the definitions of f(x) and g(x) below, find the value of g(f(-3)). f(x) = 5x + 11 g(x) = x2 + 4x – 11 ​

Answers

Answer:

g(f(-3)) = -11

Step-by-step explanation:

First, we evaluate f(-3) and then plug that value into g(x) for x:

f(x) = 5x + 11

f(-3) = 5(-3) + 11 = -15 + 11 = -4

Therefore:

g(f(-3)) = (-4)^2 + 4(-4) - 11 = 16 - 16 - 11 = 0 - 11 = -11

Answer: -11

Step-by-step explanation:

Find the value of g(f(-3)) given the two equations:

f(x) = 5x + 11

g(x) = x² + 4x - 11

Plug -3 into equation f(x).

f(-3) = 5(-3) + 11

Solve for f(x).

-4 = f(-3)

Plug -4 into the equation of g(x).

g(-4) = (-4)² + 4(-4) - 11

Solve for g(x).

g(-4) = (16) + (-16) - 11

g(-4) = -11

The value of g(f(-3)) is -11.

PLS HELP ASAP
x^2 - 4x-1=0
Solve using formula

Answers

Answer:

Your answer would be x=2±√5

Step-by-step explanation:

Multiply.

3 1/2 times 2 2/3

Answers

Answer:

Step-by-step explanation:

3 1/2 x 2 2/3 = 9 2/6 which simplifies to 9 1/3

What the answer is please

Answers

Answer:its the first one

Step-by-step explanation:

becuase it tells more explanation if you look at the answer or what im saying is problem to make it more simpler.

Find the derivative of the function y = ln(3t+4)

Answers

Answer:

3 / (3t+4) is the answer

Helpppppppppppppppppppppppp

Answers

i’d say 21 and -1 :)
21 * -1 = -21
21 - 1 = 20

[tex]xy =-21~~.....(i)\\\\x+ y=20~~....(ii)\\\\\text{From equation (i):}\\\\xy = -21 \implies y = -\dfrac{21}x~~.....(iii)\\\\\text{Substitute y in equation (ii):}\\\\x - \dfrac{21}x = 20\\\\\implies x^2 -20x -21= 0\\\\\implies x^2 - 21x + x-21=0\\\\\implies x(x-21) +(x-21) =0\\\\\implies (x+1)(x-21)=0\\\\\implies x = -1 ~~\text{or}~~ x =21\\\\\text{Substitute x in equation (iii):}\\\\y = 21 ~~ \text{or}~~ y = -1\\\\\text{Hence,}~ (x,y)=(21,-1) ~~ \text{or}~~ (x,y) = (-1,21)[/tex]

Jessica's dog weighs 117 pounds. Her dog weighs 3 times as much as Evan's dog weighs.

How much does Evan's dog weigh?

Answers

Answer:

the answer is expkained below

Answer:

Evans dog would weigh 39 pounds

Step-by-step explanation:

117= 3 × X

Take 117 and divide it by 3 and the answer we would get is 39

117 ÷ 3 = 39

To double check the answer we could multiply 39 by 3 to see if we 117.

39 × 3 = 117

X= 39 pounds, so Evans dog is 39 pounds


Melanie read 52 pages in 1 hours. If she continues reading at the same rate, how
many pages will she read in an hour?

Answers

If she read 52 pages in one hour, then she'll continue at a rate of 52 pages per hour.

Answer:

52 pages

Step-by-step explanation:

Since she reads 52 pages in 1 hour we multiply 52 by the amount of hours she reads.

52 pages times 1 hour equals 52 pages.

52 x 1 = 52

solve pls brainliest

Answers

Answer:

40

Step-by-step explanation:

LCD = 40
9/8 and 1/10 = 45/40 and 4/40

Help help math please help help help help

Answers

Answer:

Answered is x= 55x

Step-by-step explanation:

13x+10 * 12x+20

soln:

or, 13x+12x+10+20

or, 25x+30

:., therefore, x=55x

How to determine the domain and range of a continuous graph

Answers

Answer:

Step-by-step explanation:

Another way to identify the domain and range of functions is by using graphs. Because the domain refers to the set of possible input values, the domain of a graph consists of all the input values shown on the x-axis. The range is the set of possible output values, which are shown on the y-axis.                                        

Solve ^3/x^2-8=2 pls help

Answers

Answer:

its the first one

Step-by-step explanation:

What is the answer to
2 3/8 - 1 5/8 =

Answers

Answer:

6/8

Step-by-step explanation:

you have to convert each fraction into an improper. because the denominators are already the same, you dont have to worry. once you have it as an impropper, you can now subtract it. 19/8 - 13/8 = 6/8

reduce if you can

Solve for z.
57 = –10z +7

Answers

Answer:

z = -5

Step-by-step explanation:

Hi there!

We are given the equation 57 = -10z + 7, and we want to solve for z

In order to solve an equation for a variable, we want to isolate that variable on one side; in other words, we want just z on one side of the equation.

So that means that we'll need to get rid of everything else that's also on the right side. That starts with subtracting 7 from both sides:

57 = -10z + 7

-7             -7

_____________

50 = -10z

Now on the right side, there aren't any other extra terms, but remember: we want just z (also written as 1z, with the coefficient of 1), not z written with a coefficient of -10

If you divide a number by itself, the result is 1. For example. [tex]\frac{3}{3}[/tex]= 1. So in order to get a coefficient of 1, let's divide both sides by -10

[tex]\frac{50}{-10} = \frac{-10z}{-10}[/tex]

Divide, and cancel:

The zeros cancel out, leaving the equation as:

[tex]\frac{5}{-1} = \frac{-1z}{-1}[/tex]

Dividing a number by -1 is pretty much the same as multiplying a number by -1; it simply changes the sign of the number

So 5/-1 will become -5, while -1z/-1 will become 1z, or z

Hence:

-5 = z, or written the other way: z = -5

We found z.

Hope this helps!

This circle is centered at the point (3,2) and the length of its radius is 5 what is the equation of the circle

Answers

Answer:(x-3)² + (y-2)² = 25

Step-by-step explanation:

A circle's equation is (x-h)² + (y-k)² = r². When centered at the origin, h and k equal 0. If you shift the circle, say, one unit up, then k equals 1, and the equation is x² + (y-1)² = r².

So for your circle, the equation would be (x-3)² + (y-2)² = 5² or (x-3)² + (y-2)² = 25.

Answer:

(x - 3)² + (y - 2)² = 25

Step-by-step explanation:

The equation of a circle in standard form is

(x - h)² + (y - k)² = r²

where (h, k ) are the coordinates of the centre and r is the radius

Here (h, k ) = (3, 2 ) and r = 5 , then

(x - 3)² + (y - 2)² = 5² , that is

(x - 3)² + (y - 2)² = 25 ← equation of circle

please answer fully ?/'//////////////////////

Answers

Answer:

17.5

Step-by-step explanation:

i solved it and got that answer. hope this helps =)

A new cell phone costs $108.99 in the store. What would your total cost be if the sales tax is 4.5%? Round your answer to the nearest cent, if necessary.

Answers

Answer: $113.89

Step-by-step explanation:

108.99 * 0.045

= 4.90455

108.99 + 4.90455

= 113.89455

$113.89

Answer:

Total Cost = $113.89

Step-by-step explanation:

Total Cost = Cell phone cost + sale Tax % ( cell phone cost)

Total Cost = $108. 99 + .045 × $108.99

Total Cost = $108.99 + $4.90455

Total Cost = $108.99 + $4.90

Total Cost = $113.89

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