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adelina 88 [10]
3 years ago
11

To study the effectiveness of vitamin C in preventing colds, a researcher recruited 200 volunteers. She randomly assigned 100 of

them to take vitamin C for 10 weeks and the remaining 100 to take nothing. The 200 participants recorded how many colds they had during the 10 weeks. The two groups were compared, and the researcher announced that taking vitamin C reduces the frequency of colds.
Mathematics
1 answer:
Paul [167]3 years ago
5 0

Answer:

The claim made by the researcher lacks the validity on basis of reasons as indicated in the explanation.

Step-by-step explanation:

The claim made by the researcher is not valid on basis of following reasons:

  1. Interacting variables are not mapped accurately. The additional variables as the health status of the volunteers, eating and fitness habits are not considered in the consideration. This results in a in complete validation.
  2. The placebo effect is not catered accordingly. As the half of the volunteers are taking nothing, this is not the direct influence of the placebo and thus double-blinded testing for placebo effect is to be ensured in future experiments.
  3. The environmental effects are not considered as the effect under study is dependent on the environmental effects, thus the claim is biased and the generalization is not valid.
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Yes

Step-by-step explanation:

A right angle means that the lines will create an L or X or T when they intersect. This is exactly the definition of perpendicular, that the shapes will intersect and create at least one right angle.

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(10.05 LC)
loris [4]

Answer:

Cos x = \frac{base}{hypotenuse}=\frac{\sqrt{3} }{2}

Tan x = \frac{perpendicular}{base} = \frac{1}{\sqrt{3} }

Step-by-step explanation:

Sin x = \frac{perpendicular}{hypotenuse} = \frac{1}{2}

So, Perp = 1 and hyp = 2

<em>Putting this in Pythagorean theorem to get the base</em>

c^2 = a^2+b^2

a^2 = c^2-b^2

base ² = 4-1

base² = 3

<em>Taking square root on both sides</em>

Base = \sqrt{3}

Now

Cos x = \frac{base}{hypotenuse}=\frac{\sqrt{3} }{2}

Tan x = \frac{perpendicular}{base} = \frac{1}{\sqrt{3} }

5 0
4 years ago
Jordan and Sydney work at a dry cleaners ironing shirts. Jordan can iron 20 shirts per hour, and Sydney can iron 25 shirts per h
KiRa [710]

Answer: Jordan worked for 10 hours and Sydney worked for 6 hours.

Step-by-step explanation:

Let x represent the number of hours

that Jordan worked.

Let x represent the number of hours that Sydney worked.

Jordan can iron 20 shirts per hour, and Sydney can iron 25 shirts per hour. They ironed 350 shirts between them. It means that

20x + 25y = 350- - - - - - - - - - - 1

Jordan worked 4 more hours than Sydney. It means that

x = y + 4

Substituting x = y + 4 into equation 1, it becomes

20(y + 4) + 25y = 350

20y + 80 + 25y = 350

20y + 25y = 350 - 80

45y = 270

y = 270/45

y = 6

x = y + 4 = 6 + 4

x = 10

6 0
3 years ago
What is the answer to this- 9th-grade geometry
NemiM [27]

Answer:

AB is congruent is CD.  (Last one)

Step-by-step explanation:

Hypotenuse leg is when the hypotenuse and ONE (you only need one, not two) leg of the triangle are congruent in a RIGHT triangle.

In the image, you already know that it is a right triangle and you know that the hypotenuse are congruent (Reflexive Prop) .You just need to know that the legs are congruent.  So you choose which one has the legs congruent.  The leg pairs that can be congruent are AD and CB or DC and AB.  The only one that matches this is the last one

8 0
3 years ago
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