Vitamin D is important for the metabolism of calcium and exposure to sunshine is an important source of vitamin D. A researcher wanted to determine whether osteoperosis was associated with a lack of exposure to sunshine. He selected a sample of 250 women with osteoperosis and an equal number of women without osteoperosis. The two groups were matched - in other words they were similar in terms of age, diet, occupation, and exercise levels. Histories on exposure to sunshine over the previous twenty years were obtained for all women. The total number of hours that each woman had been exposed to sunshine in the previous twenty years was estimated. The amount of exposure to sunshine was compared for the two groups.

Required:
a. Determine whether this is a controlled experiment or an observational study.
b. Identify the treatment variable.

Answers

Answer 1

Answer:

Vitamin D and Osteoporosis

a. This is an observational study.  The researcher is trying to observe the two groups of women who suffer from osteoporosis.  She did not apply any treatment on any group, as is the case with experimental researches.

b. The treatment variable is the amount of exposure to sunshine.

Step-by-step explanation:

This study is an observational research because the researcher lacks the control over the variables, especially the amount of exposure to sunshine.  She is merely observing what has occurred previously.  On the other hand, an experimental study will involve the application of some treatments to one group of women and then the recording of the effects.  But in this case, the researcher merely recorded the effects that had occurred without applying any treatment to any group.


Related Questions

► Use what you learned to solve these problems.
The cost of a cross-stitch project is a function of the number of
skeins of embroidery floss it requires. The table shows the cost
of projects that use different amounts of embroidery floss What
is the equation of the linear function that models this situation?
Show your work
51125
$13.50
$1650
SOLUTION

Answers

13..hshdhdjjsjdjdjejejejejejejejejejdjdhehebddjdjdjd

Which circle shows AB that measures 60 degrees

Answers

Answer:

The central angle is the measure of minor arc AB. The central angle here is 60 degrees, shown by the third circle down from the top. This is the right answer.

Step-by-step explanation:https://brainly.com/question/12790519#:~:text=The%20central%20angle%20is%20the,This%20is%20the%20right%20answer.

The radius of a quarter circle is 2 yards. What is the quarter circle's perimeter?

Answers

12.57.
The perimeter (circumference) of a circle can be found with either c= πd or c=2πr
(The d is diameter)

This object is made with six identical cubes. Each cube edge is 5 inches long. What is the surface area of the object in square inches

Answers

Answer:

Cube

Solve for surface area

A=150in²

a Edge

5

in

PLEASE ANSWER WILL GIVE BRAINLIEST

Answers

Answer:

The answer is B

Step-by-step explanation:

V=lwh

3=15·15·20

3=1500

Find the value of x. Round to the nearest tenth.

Answers

Answer:

x = 11.8

Step-by-step explanation:

Side a = 11.78983

Side b = 3

Side c = 10

Angle ∠A = 120° = 2.0944 rad = 2/3π

Angle ∠B = 12.731° = 12°43'50" = 0.22219 rad

Angle ∠C = 47.269° = 47°16'10" = 0.82501 rad

The answer for x is 11.8

Can you guys please help!

Answers

Answer:

5 for the first and 4x for the second one also plz give heart

Step-by-step explanation:

i just know



If (y + 1) varies directly as square root of x and y =14 when x = 27, find the value of y when
x = 64 without finding the variation constant.​

Answers

Answer:

22.1 or 22

Step-by-step explanation:

Y + 1 varies√x

Y + 1 = K√x ( k is costant)

so we solve for K

given: 14 + 1 = K√27

15 = K√27

divide both sides by √27

15/√27 = K

to find the value of y

y + 1 = 15/√27 (8) : substitute K for 15/√27

Y + 1 = 120/√27

i.e Y = 120/√27 - 1

Y = 23.1 - 1

Y = 22.1 or 22

find the value of x and round to the nearest tenth (geometry)

Answers

Answer and Step-by-step explanation:

Just flip the triangle upside down, to make it look more sense.

   (Angle) 17

    |\

x   |  \ 47

    |__\

We will use the sine trig function to solve for x.

sin(17) = [tex]\frac{x}{47}[/tex]

Multiply by 47 to both sides.

47(sin(17)) = x

Now input into a calculator and solve.

x = 13.74147012

x ≈ 13.7 is the answer.

Let h(t) =-16t2 + 5t + 1. What is h(1)?

Answers

Answer:

Step-by-step explanation:

Hhggggy

answer:




step-by-step explanation
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Guys I suck at this stuff so can someone Just PLEASE HELP ME

Answers

Answer:

I only

Step-by-step explanation:

The others have irrational & unsolvable numbers!

Hope that helps!

A random sample of 200 adult residents in the U.S reveals that the mean minutes of sleep they received the night prior to the interview was 528 minutes with a standard deviation of 141 minutes. Using a computer, a random sample of 200 observations was taken (with replacement) from these data and an average was computed and recorded. This was repeated 10,000 times and a visualization was made of this sampling distribution. The mean of the sampling distribution was 528 minutes and the standard deviation was 10 minutes. The sampling distribution was symmetric and unimodal. Which of the following is an approximate 95% confidence interval for the mean amount of sleep of all US residents?
a. Lower bound: 528-141, upper bound: 528+141; (387, 669)
b. Lower bound: 528-10, Upper bound: 528+10; (518,538)
c. Lower bound: 528-20141, upper bound: 528 * 2*141; 246,810)
d. lower bound: 528-2-10, upper bound: 528+2*10; (508, 548)

Answers

Answer:

d. lower bound: 528-2-10, upper bound: 528+2*10; (508, 548)

Step-by-step explanation:

The computation of the approximate 95% confidence interval is shown below:

Given that

mean = 528,

standard deviation = 10

[tex]Mean \mp z_{\frac{0.05}{2}}\times standard\ deviation \\\\=528 \mp 2 \times 10\\\\=(508,548)[/tex]

hence, the correct option is d.

The confidence interval gives a range of estimate for the true population mean at a given confidence level. The confidence interval for the mean is lower bound: 528-2-10, upper bound: 528+2*10; (508, 548)

The confidence interval for the mean is obtained using the relation :

μ ± Z*σZ* = 95% critical level = ±1.96μ = sample mean = 528σ = standard deviation = 10 minutes

Plugging in the values :

528 ± (1.96 × (10))

Approximating Z* (1.96) = 2.00

Lower boundary = 528 - (2 × 10) = 528 - 20 = 508

Upper boundary = 528 + (2 × 10) = 528 + 20 = 548

Therefore, the confidence interval is lower bound: 528-2-10, upper bound: 528+2*10; (508, 548)

Helppppppp me with question 5 Tuesday pleaseeeeee

Answers

Answer:

n=19

Step-by-step explanation:

5+14=n

19=n

SOLVING THE SYSTEM BY ELIMINATION!

Answers

Distribute the 2 to get the pink box

10x + 2y = 18
Then if we are subtracting the bottom equation from the pink box
10x + 2y = 18
-(10x -7y = -18)
9y = 36
y = 4

What is the probability of randomly selecting a card from a standard 52 card deck and having the card be a face card or an even numbered card?

A) 5.16
B) 16.5
C) .165
D) .615

Answers

I think c but don’t take my word

eight percent multiped by fifty

Answers

Answer:

4

Step-by-step explanation:

Turn the percentage into a decimal and multiply.

8% -> 0.08

0.08 * 50 = 4

Best of Luck!

Answer:

4

Step-by-step explanation:

8% times 50 is the same as 8% of fifty


The sum of three numbers is 10. The first number minus the second plus the third is 6. The first minus the third is 2 more than the second. Find the numbers

Answers

This is an answer I wrote last year check it out I have it in my progress
6+2+2=10
6-2+2=6
6-2=4 and 2 times 2 is 4 so 6-2 is 2 more than the second number which is 2.

So the numbers are 6, 2 and 2.

use ⧍ABC and assume B = 90°.
2. Findcgiven m∠A=57° and a=22

Answers

Answer:

1

Step-by-step explanation:

Answer:    c = 14.287  approximately

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

Work Shown:

Refer to the diagram below. Note how side a is opposite angle A, and side c is opposite angle C.

tan(angle) = opposite/adjacent

tan(A) = a/c

tan(57) = 22/c

c*tan(57) = 22

c = 22/tan(57)

c = 14.2869670503452

c = 14.287

This value is approximate. Make sure your calculator is in degree mode

The ratio of cows to goats in a farm is 3:2 if there are 210 more cows than goats how many animals are there in the farm​

Answers

Answer: 350 animals altogether.

Explanation: We need to find the number of goats and add that to the 210 cows.

Since we have a ratio, we can use the equation 3/2=210/x.

Cross multiplying gives us 3x=420, where x is 140 goats.

Finally, 140+210=350.

How do I write this equation without fractions or decimals?
2-(3/4)x=2/5

Answers

multiply each side by 20
40 - 15x = 8

Determine if the following function is even, odd or neither.
f(x) = 4x2 – 8x + 5

Answers

9514 1404 393

Answer:

  neither

Step-by-step explanation:

A polynomial consisting of even-degree terms only is even.

A polynomial consisting of odd-degree terms only is odd.

The given f(x) polynomial has both even- and odd-degree terms, so is neither.

In the parallelogram below, solve for Y
Options
4
10
25
100

Answers

Answer:

x = 4

y = 4

Step-by-step explanation:

the front triangle has two 40° angles (sum of all ∡'s must be 180°)

the unlabeled lower-left angle then is 40°; this angle corresponds to the angle in the other triangle labeled as 10y°

therefore, 10y = 40 so y = 4

Since opposite angles in a parallelogram are congruent then we can write:

40° + 25x° = 100° + 10(4)°

25x° = 140 - 40°

25x = 100°

x = 4

A server sees 90 customers over 6 hours. How many customers did they see in 1 hour? *

Answers

Answer:

They saw 15 customers per hour.

Step-by-step explanation:

Fifteen customers
Because its 90 divided by 6 basically

The sum of the angle measures of the polygon is 540°. Write and solve an equation to find the value of x.

An equation is ____=540​
The solution is x=____

Answers

in figure

85+5n+5n+5n+5f+5n-10=540

20n+80=540

20n= 460

x=23

10 POINTS
Which of the following situations can be represented by 145 ?
1. Renee has 14 feet of ribbon to that she will cut into 5 pieces of equal length.
2.Mike has 14 packs of trading cards with 5 in each pack.
3.Rama opens 5 bags of trail mix, which she will split equally into 14 bowls.
4.Payton takes 5 pencils from a box containing 14 pencils.

Answers

1 and 2 are the answers

Answer:

2

Step-by-step explanation:

3. represents 514

4. represents 514

You are thinking of opening a small copy shop. It costs $5000 to rent a copier for a year, and it costs $0.03 per copy to operate the copier. Other fixed costs of running the store will amount to $400 per month. You plan to charge an average of $0.10 per copy, and the store will be open 365 days per year. Each copier can make up to 100,000 copies per year.

Required:
a. For one to five copiers rented and daily demands of 500, 1000, 1500, and 2000 copies per day, find annual profit. That is, find annual profit for each of these combinations of copiers rented and daily demand.
b. If you rent three copiers, what daily demand for copies will allow you to break even?
c. Graph profit as a function of the number of copiers for a daily demand of 500 copies; for a daily demand of 2000 copies. Interpret your graphs.

Answers

Answer and explanation:

A. To calculate annual profit, we find:

Total income - total cost for the 365 days in a year

Total income for different daily demands:

For 500 copies= 500×365×0.10=$18250

For 1000 copies= 1000×365×0.10=$36500

For 1500 copies=1500×365×0.10=$54750

For 2000 copies=2000×365×0.10=$73000

Total cost using five copiers= 400×12+5000×5+500000×0.03= $44800

Total cost using four copiers=

400×12+5000×5+400000×0.03=

$36800

Annual profit with daily demand of 2000 and five copiers available= $73000-$44800= $28200

B.

Ashley, Bob, Claire, and Daniel are among 13 students who entered a lottery to win a free vacation to Paris.
Only 4 people will be chosen at random. What is the probability that Ashley, Bob, Claire, and Daniel will be
chosen? (Lesson 19.3) (1 point)

Answers

Answer:

0.0014 = 0.14% probability that Ashley, Bob, Claire, and Daniel will be chosen.

Step-by-step explanation:

A probability is the number of desired outcomes divided by the number of total outcomes.

The order in which the students are chosen is not important, so the combinations formula is used to solve this question.

Combinations formula:

[tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

Desired outcomes:

4 students from a set of 4(Ashley, Bob, Claire, and Daniel). So

[tex]D = C_{4,4} = \frac{4!}{4!(4-4)!} = 1[/tex]

Total outcomes:

4 students from a set of 13(number of students in the lottery). So

[tex]T = C_{13,4} = \frac{13!}{4!(13-4)!} = 715[/tex]

Probability:

[tex]p = \frac{D}{T} = \frac{1}{715} = 0.0014[/tex]

0.0014 = 0.14% probability that Ashley, Bob, Claire, and Daniel will be chosen.

Pls help me I’ll give out brainliest please dont answer if you don’t know

Answers

Answer:

$8.65

Step-by-step explanation:

1.25+4.75+2.50=8.5

8.5+0.056(5.6%)=8.65

Of 20 students, 9 are girls

% of girls

% of boys

Answers

Girls: 45%
Boys : 55%

Answer:

45% and 55%

Step-by-step explanation:

Total student = 20

No of Girls = 9

No of boys = Total student - No of Girls

                  =20-9

                  =11

Percentage of Girls = (No of Girls / Total student) * 100

                           = (9/20)*100

                           = 45 %

Percentage of Boys = (No of Boys/ Total student) * 100

                           = (11/20)*100

                           = 55 %

A sound wave travels at 330m/s and has a wavelength of 2 m. calculate its frequency and period.

Answers

Answer:

frequency= 165Hz

period= [tex]\frac{1}{165}[/tex]

Step-by-step explanation:

1. To calculate the frequency using the formula:

f = v/λ

where,

f=frequency (what the question asked)

v=speed of wave (given in the question=330m/s)

λ=wavelength (given in the question=2m)

SO,

[tex]f=\frac{330}{2}[/tex]

= 165Hz

2. To calculate the period use the formula:

since [tex]f=\frac{1}{T}[/tex]

therefore, [tex]T=\frac{1}{f}[/tex]

where,

f= frequency (what we solved above=165Hz)

T= period (what the question asked)

SO,

[tex]T=\frac{1}{165}[/tex]

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