For each of the following cases [(a), (b), and (c)], (I) state whether the study should be observational or experimental. (II) state whether the study should be run blind, doubleblind, or neither. If the study should be run blind or double-blind, who should be blinded?(a) An investigation of whether taking aspirin reduces one’s chance of having a heart attack.(b) An investigation of whether babies born into poor families (family income below $25,000) are more likely to weigh less than 5.5 pounds at birth than babies born into wealthy families (family income above $65,000).(c) An investigation of whether the size of the midsagittal plane of the anterior commisssure (a part of the brain) of a man is related to the sexual orientation of the man.

Answers

Answer 1

Answer:

(a) An investigation of whether taking aspirin reduces one’s chance of having a heart attack.

Experimental

Neither blind nor double-blind (unless a placebo is being administered to some participants).

(b) An investigation of whether babies born into poor families (family income below $25,000) are more likely to weigh less than 5.5 pounds at birth than babies born into wealthy families (family income above $65,000).

Observational

There is no blinding issue here.

(c) An investigation of whether the size of the midsagittal plane of the anterior commissure (a part of the brain) of a man is related to the sexual orientation of the man.

Observational

There is no blinding issue here.

Step-by-step explanation:

An observational study happens where some variables are observed to determine their correlations.   On the other hand, in experimental studies, the researcher controls certain variables to determine causality.  Therefore, an experimental study provides evidence of cause and effect, like in (a) above.


Related Questions

A jewelry store is having a 45% off sale for all necklaces. During this sale, what is the cost of a necklace that regularly costs $59.98?​

Answers

Answer:

32.99

Step-by-step explanation:

59.98(45%)=26.99

59.98-26.99=32.99

Answer:

$32.99, the discount took off $26.99.

Step-by-step explanation:

Good luck!

The constant of proportionality of this table is

Cups of

blue paint

cups of

yellow paint

2 10
1

Answers

Answer:

Step-by-step explanation:

1/2

Herman is standing on a ladder that is partly in a hole. He starts out on a rung that is 6 feet under ground, climbs up 14 feet, then climbs down 11 feet. What is Herman’s final position, relative to ground level?

Answers

Answer:

Are there answers

Step-by-step explanation:

Answer:

answer

Herman is standing on a ladder that is partly in a hole. He starts out on a rung that is 6 feet under ground, climbs up 14 feet, then climbs down 11 feet. ...

PLEASE HELP IM TIMEZ) What is the value of the arithmetic series below? A. B. C. D.

Answers

Answer:

id say its C but I'm not sure

A map has a scale of 2 in: 6 mi. If Clayton
and Centerville are 10 in apart on the map
then how far apart are the real cities?

Answers

Both cities are 30 miles apart in real

1. You are eating on a Tootsie Roll Lollipop that is in the shape of a sphere. It is giving up volume at a steady rate of 0.25 in3 /min. How fast will the radius be decreasing when the Tootsie Roll Pop is .75 inches across?

Answers

Answer:

Step-by-step explanation:

Since the Tootsie Roll lollipop is a sphere

volume of sphere= [tex]\frac{4}{3}piR^3[/tex] = -0.25 [tex]in^3/min[/tex]

the negative sign indicates that the volume is decreasing

upon differentiating

as the diameter given is =0.75 so radius will be = 0.375

[tex]dV/dt = 4piR^2*dR/dt[/tex]

so [tex]dR/dt = 0.25/4*3.14 *(0.375)^2[/tex]

So the radius is decreasing at the rate of dR/dt= 0.142in/min

Consider the experiment of selecting a playing card from a deck of 52 playing cards. Each card corresponds to a sample point with a 1 52 probability.

Required:
a. List the sample points in the event a jack is selected.
b. List the sample points in the event a club is selected.
c. List the sample points in the event a face card ( jack, queen, or king) is selected.
d. Find the probabilities associated with each of the events in parts (a), (b), and (c).

Answers

Answer:

Kindly check explanation

Step-by-step explanation:

A deck of card:

Number of hearts = 13

Diamond = 13

Spade = 13

Club = 13

Each of heart, club diamond and spade has is numbered from (2,3,4,5,6,7,8,9,10,Ace, queen, Jack, king)

Hence, a club, diamond, spade and heart has one of each of the above numbers.

a. List the sample points in the event a jack is selected.

Jack : ( heart, club, diamond, spade)

B.) club is selected :

Cub : (Ace, 2, 3,4,5,6,7,8,9,10,king,queen,jack)

C)

Jack : ( heart, club, diamond, spade)

Queen : (heart, club, diamond, spade)

King : (heart, club, diamond, spade)

D) probability = required outcome / Total possible outcomes

P(jack selected) = 4 /52 = 1/13

P(club selected). = 13/52 = 1/4

P(face card selected) = 12 / 52 = 3/13

Find the selling price of each item original plate price of gold fish at $7.65 discount 10%

Answers

Answer:

6.88 is what I think you're looking for

Step-by-step explanation:

Find the product of (18k+ 2m)(m + k)

Answers

Answer:

18k^2+2m^2+20km

Step-by-step explanation:

please help!! I'm really confused

Answers

Answer:

Point a is correct.

Step-by-step explanation:

hope I helped.

10a^2b^0 for a=–3, b=–8

Answers

Answer:

90

Step-by-step explanation:

Substitute a = -3 and b = -8 to the expression 10a²b⁰:

10(-3)²(-8)⁰ = 10(9)(1) = 90

a⁰ = 1 for any real number

Answer:

90

Step-by-step explanation:

10a^2b^0

Let a=–3, b=–8

10 (-3)^2 ( -8)^0

10 * 9 *1

90

A car sharing service offers a membership plan with a $50 per month fee that includes 10 hours of driving each month and charges $9 for each additional hour
(A) Write a piecewise definition of the cost F(x) for a month in which a member uses a car for x hours
(B) Graph F(x) for 0 < x s 15
(C) Find lim x--->10 F(x), lim x--->10F(x), and lim x--->10F(x), which- ever exist.

Answers

Answer:

A)  F(x) = 50 + ( x - 10 )*9  

B) Graph

C) lim ( x ⇒ 10) F(x) = 50

Step-by-step explanation:

A) F(x) = 50 + ( x - 10 )*9       since the first 10 hours are included in initial fee

B) In Annex

C) lim (x ⇒ 10) F(x) = 50 + ( 10 -10)*9

lim ( x ⇒ 10) F(x) = 50 + 0

lim ( x ⇒ 10) F(x) = 50

Jackson has 429 matchbox cars in his collection. If 4 out of 9 are blue cards, how many are not blue

Answers

4/9= 5 so then you would do 429 divided by 5 and that gives you 85.8

PLEASE ANSWER I WILL GIVE YOU BRAINLIEST!
Name the points which satisfy the conditions. In the second quadrant

Answers

9514 1404 393

Answer:

  C, M

Step-by-step explanation:

The second quadrant is the upper left quadrant. There, x-values will be negative and y-values will be positive.

__

Point G is on the boundary with the 3rd quadrant, so is probably not considered to be in either of those quadrants.

Answer: C M

Step-by-step explanation:

What is the area of a rectangle with sides measuring 2x+3 and 3x-1 feet

Answers

Here is your answer
the answer is 6x^2+7x-3
u would foils the two terms as shown below

The giber family purchased a house for 127,000 the first five years they paid off 12,000 each year . How much money do they still owe on the house ?

Answers

Answer:

dndnfhhfbdhdndndnmdmdndndnen

$67,000
12,000x5= 60,000
127,000-60,000= 67,000

What is the measure of angle F?
E. 20
D. 90
F.?

Answers

Answer:

the answer would be 70 because you take 90-20 and you get 70. you have a 90 degree angle is what you're working on right now

Step-by-step explanation:

Please help!!!- Find the measure of the angle in bold.
Need help to figure out to solve this.

Answers

Answer:

11x-6+(19x+6)=180°

11x+19x-6+6=180°

30x=180

x=180/30

x=6

it means that

19x+6=19*6+6=114+6=120°

A box is formed by cutting squares from the four corners of a sheet of paper and folding up the sides.
Suppose the paper is 7"-wide by 9"-long.
a. Estimate the maximum volume for this box?
b. What cutout length produces the maximum volume?

Answers

Answer:

B

Step-by-step explanation:

To answer this question it is necessary to find the volume of the box as a function of "x", and apply the concepts of a maximum of a function.

The solution is:

a) V (max) = 36.6 in³

b) x = 1.3 in

The volume of a cube is:

V(c) = w×L×h  ( in³)

In this case, cutting the length  "x" from each side, means:

wide of the box    ( w - 2×x )   equal to  ( 7 - 2×x )

Length of the box ( L - 2×x )   equal to  ( 9 - 2×x )

The height  is  x

Then the volume of the box,  as a function of x is:

V(x) = ( 7 - 2×x ) × ( 9 -2×x ) × x

V(x) = ( 63 - 14×x - 18×x + 4×x²)×x

V(x) = 4×x³ - 32×x² + 63×x

Tacking derivatives,  on both sides of the equation

V´(x) = 12×x² - 64 ×x + 63

If   V´(x) = 0      then      12×x² - 64 ×x + 63 = 0

This expression is a second-degree equation, solving for x

x₁,₂ = [ 64 ± √ (64)² - 4×12*63

x₁ =  ( 64 + 32.74 )/ 24

x₁ = 4.03     this value  will bring us an unfeasible solution,  since it is not possible to cut 2×4 in from a piece of paper of 7 in ( therefore we dismiss that value)

x₂ = ( 64 - 32.74)/24

x₂ = 1.30 in

The  maximum volume of the box is:

V(max) = ( 7 - 2.60) × ( 9 - 2.60)×1.3

V(max) = 4.4 × 6.4 × 1.3

V(max) = 36.60 in³

To chek for maximum value of V when x = 1.3

we find the second derivative of V  V´´,  and substitute the value of x = 1.3,    if the relation is smaller than 0,  we have a maximum value of V

V´´(x) = 24×x - 64 for x = 1.3

V´´(x) = 24× 1.3 - 64            ⇒   V´´(x) < 0

Then the value  x = 1.3 will bring maximum value for V

Related Link: https://brainly.com/question/13581879

Which best describes the solution set of the compound inequality below? 2 + x ≤ 3x – 6 ≤ 12 4 ≤ x ≤ 9 4 ≤ x ≤ 6 –2 ≤ x ≤ 2 –2 ≤ x ≤ 3

Answers

Answer:

Im sure you dont need this anymore but in case someone else does, im pretty sure the answer is B

Answer:

B is tha right answer

Step-by-step explanation:

what is 4/6+2/3.?(these are fractions, you're just adding fractions)

Answers

Answer:

4/3

Step-by-step explanation:

Multiply 2 by 2, and get 4, then we multiply 3 by 2 and get 6.

Since our denominators match, we can add the numerators. 4 + 4 = 8. That gives us the sum, which is 8/6. Then you divide by 2.  So 8/6 / 2 gives you 4/3.

Answer:

4/3 or 1 1/3

Step-by-step explanation:

1. 4/6 + 2/3

2. 4/6 + 4/6          You have to find the LCM (least common multiple) of the two  denominators. In this case it would be 6. You have to multiply 3 by 2 to get 6. What you do to the bottom you also do to the top so you have to also multiply the numerator (2) by 2.

3. 4/3 or 1 1/3       Afterward, you just have to add straight across without changing the denominator and then if you need to simplify you simplify. Without simplifying, you would get 8/6, but, most teachers will mark it as wrong if you don't simplify. You can then change the improper fraction into a mixed number depending on what your teacher wants.

Suppose that the probability that a person books a hotel using an online travel website is 0.68. For the question that​ follows, consider a sample of fifteen randomly selected people who recently booked a hotel.

What is the probability that at least fourteen out of fifteen people used an online travel website when they booked their​ hotel? Round to three decimal places.

A.0.028
B.0.025
C.0.323
D.0.978

Answers

Answer:

the answer is d because 0.978 cool number like yaaaa.

Step-by-step explanation:

It’s d)0.978
Hope it helps
Have a good day
Oh and your the best

An item has a listed price of $80. If the sales tax rate is 8%, how much is the sales tax (in dollars)?

Answers

Answer:

$6.40

Step-by-step explanation:

u have to multiply 80 by 0.08 (tax percent in decimal form)

Answer:

$6.4

Step-by-step explanation:

all you have to do is find 8% of 80 by doing 8x8, which equals 64, then dividing by 10. That gives you 6.4. Then check it on a calculator to make sure you did it correctly

Complete the point-slope equation of the line through (2,3)(7,4)
y-4=

Answers

y-4=1/5(x-7) is the answer

a diver descended 84 feet in 6 minutes. What was the divers change in depth per minute? Write and expression with a solution

Answers

Answer:

14 depth per minute

Step-by-step explanation:

84/6 = 14

Solve:
a.) 5(x - 2) > -15
AND
b.) x/1 - 9 < -10

Answers

Answer:

a.) x>-1

b.) x/1 - 9 < -10

Step-by-step explanation:

a.)

5(x - 2) > -15

(divide both sides)

x-2>-3

(move the constant to the right)

x>-3+2

(calculate)

x>-1

(answer)

b.)

x/1 - 9 < -10

(divide)

x-9<-10

(move the constant to the right)

x<-10+9

(calculate)

x/1 - 9 < -10

(answer)

find the values of the six trigonometric functions for angle theta in standard position if a point with the coordinates (1, -8) lies on its terminal side

Answers

Answer:

cosФ = [tex]\frac{1}{\sqrt{65}}[/tex] , sinФ = [tex]-\frac{8}{\sqrt{65}}[/tex] , tanФ = -8, secФ = [tex]\sqrt{65}[/tex] , cscФ = [tex]-\frac{\sqrt{65}}{8}[/tex] , cotФ = [tex]-\frac{1}{8}[/tex]

Step-by-step explanation:

If a point (x, y) lies on the terminal side of angle Ф in standard position, then the six trigonometry functions are:

cosФ = [tex]\frac{x}{r}[/tex]sinФ = [tex]\frac{y}{r}[/tex]tanФ = [tex]\frac{y}{x}[/tex]secФ = [tex]\frac{r}{x}[/tex]cscФ = [tex]\frac{r}{y}[/tex]cotФ = [tex]\frac{x}{y}[/tex]Where r = [tex]\sqrt{x^{2}+y^{2} }[/tex] (the length of the terminal side from the origin to point (x, y)You should find the quadrant of (x, y) to adjust the sign of each function

∵ Point (1, -8) lies on the terminal side of angle Ф in standard position

∵ x is positive and y is negative

→ That means the point lies on the 4th quadrant

∴ Angle Ф is on the 4th quadrant

∵ In the 4th quadrant cosФ and secФ only have positive values

∴ sinФ, secФ, tanФ, and cotФ have negative values

→ let us find r

∵ r = [tex]\sqrt{x^{2}+y^{2} }[/tex]

∵ x = 1 and y = -8

∴ r = [tex]\sqrt{x} \sqrt{(1)^{2}+(-8)^{2}}=\sqrt{1+64}=\sqrt{65}[/tex]

→ Use the rules above to find the six trigonometric functions of Ф

∵ cosФ = [tex]\frac{x}{r}[/tex]

∴ cosФ = [tex]\frac{1}{\sqrt{65}}[/tex]

∵ sinФ = [tex]\frac{y}{r}[/tex]

∴ sinФ = [tex]-\frac{8}{\sqrt{65}}[/tex]

∵ tanФ = [tex]\frac{y}{x}[/tex]

∴ tanФ = [tex]-\frac{8}{1}[/tex] = -8

∵ secФ = [tex]\frac{r}{x}[/tex]

∴ secФ = [tex]\frac{\sqrt{65}}{1}[/tex] = [tex]\sqrt{65}[/tex]

∵ cscФ = [tex]\frac{r}{y}[/tex]

∴ cscФ = [tex]-\frac{\sqrt{65}}{8}[/tex]

∵ cotФ = [tex]\frac{x}{y}[/tex]

∴ cotФ = [tex]-\frac{1}{8}[/tex]    

The life span of a graphing calculator manufactured by Texas Instruments has a normal distribution with a mean of 54 months and a standard deviation of 8 months. The company guarantees that any calculator that starts malfunctioning within 36 months of the purchase will be replaced by a new one. You apply the normal model and discover that this is approximately 1.22% of their graphing calculators. Texas Instruments has sold 75 million graphing calculators world- wide. How many of these would you expect to malfunction within 3 months (and thus need to be replaced)? Explain.

Answers

Answer:

The expected number of graphing calculators that malfunctions within 3 months and need to be replaced is 915,000.

Step-by-step explanation:

Let X represents the number of graphing calculator that starts malfunctioning within 36 months of the purchase and needs to be replaced by a new one.

It is provided that X follows a normal distribution with a mean of 54 months and a standard deviation of 8 months.

Also, using the normal model it was determined that 1.22% of graphing calculator manufactured by Texas Instruments malfunctions and needs replacement.

That is,

P (X) = 0.0122

Texas Instruments has sold 75 million graphing calculators world- wide.

Compute the expected number of graphing calculators that malfunctions within 3 months and need to be replaced as follows:

E (X) = n × P (X)

        = 75 × 10⁶ × 0.0122

        = 915000

Thus, the expected number of graphing calculators that malfunctions within 3 months and need to be replaced is 915,000.

I need help. Is this right????

Answers

Answer: (I can only see stage 1 and 2 fully) Stage 1: 2 Stage 2: 4

Step-by-step explanation:

Answer:

Step-by-step explanation:

0 = 0

1 = 2

2 = 4

3 = 6

20 = 40

which number is the same as 0.000 000 1: 10^7 or 10^-7​

Answers

Answer:

= 1 × 10^-7

(scientific notation)

= 1e-7

(scientific e notation)

= 100 × 10^-9

(engineering notation)

(billionth; prefix nano- (n))

= 0.0000001

(real number)

Step-by-step explanation:

10^7 = 10000000

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