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Zinaida [17]
2 years ago
8

A tooth-whitening gel is to be tested for effectiveness. A group of 85 adults have volunteered to participate in the study. Of t

hese, 43 are to be given a gel that contains the tooth-whitening chemicals. The remaining 42 are to be given a similar-looking package of gel that does not contain the tooth-whitening chemicals. A standard method will be used to evaluate the whiteness of teeth for all participants. Then the results for the two groups will be compared. 1. After the treatment period, compare the whiteness of the 43 treated adults. 2. A placebo is not being used. 3. After the treatment period, compare the whiteness of the two groups. 4. Randomly select 85 adults to be given the treatment gel. 5. The remaining 42 adults receive the placebo gel. 6. Randomly select 43 adults to be given the treatment gel.
Mathematics
1 answer:
Lina20 [59]2 years ago
5 0

Answer:

(a) 3, 5 and 6

Step-by-step explanation:

In the experiment, 43 are to be given a gel that contains the tooth-whitening chemicals while the remaining 42 are to be given a placebo. Therefore, a placebo is used.

The 43 that will receive the gel are to be selected randomly.

After the experiment, the whiteness of the two groups will be compared to see the effect of the gel.

Therefore for the experiment to be completely random,  3, 5, and 6 apply.

(b)

For the experiment to be double-blind, the researchers who will evaluate the whiteness and interact with the subjects, and the subjects would not know which subjects received either the whitening gel or the placebo.

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This must be FALSE, because:

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If the greatest is 8, we must do 28 - 8, which gives us 20. This means that the remaining 6 players (7 - 1 = 6) made a total of 20 baskets.

However, if the fewest is 4 baskets, this means that the remaining 5 players (6 - 1 = 5) must have made a total of 16 baskets (20 - 4 = 16) and that each player must have scored 4 or more baskets each (since 4 was the fewest number of baskets made).

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Answer:

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2. The amount of fabric needed to manufacture the umbrella is 0.76 m²

3. The height of the cone, is 3.75 cm

4. The dimensions of the deck are;

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The area be 87.11 m²

5.   The dimensions of the optimal design for setting the storage area at the corner, we have;

Width = 10m

Breadth = 10 m

The dimensions of the optimal design for setting the storage area at the back of their building are;

Width = 7·√2 m

Breadth = 7·√2 m

Step-by-step explanation:

1. The amount of ice needed is given by the volume, V, of the pyramid given by V = 1/3 × Base area × Height

The base area = Base width × Base breadth = 3 × 5 = 15 m²

The pyramid height = 3.6 m

The volume of the pyramid = 1/3*15*3.6 = 18 m²

The amount of ice needed = 18 m²

2. The surface area of the umbrella = The surface area of a cone (without the base)

The surface area of a cone (without the base) = π×r×l

Where:

r = The radius of the cone = 0.4 m

l = The slant height = √(h² + r²)

h = The height of the cone = 0.45 m

l = √(0.45² + 0.4²) = 0.6021 m

The surface area = π×0.4×0.6021 = 0.76 m²

The surface area of a cone (without the base) = 0.76 m²

The surface area of the umbrella = 0.76 m²

The amount of fabric needed to manufacture the umbrella = The surface area of the umbrella = 0.76 m²

3. The volume, V, of the cone = 1/3×Base area, A, ×Height, h

The volume of the cone V = 150 cm³

The base area of the cone A = 120 cm²

Therefore we have;

V = 1/3×A×h

The height of the cone, h = 3×V/A = 3*150/120 = 3.75 cm

4. Given that the deck will have railings on three sides, we have;

Maximum dimension = The dimension of a square as it is the product of two  equal maximum obtainable numbers

Therefore, since the deck will have only three sides, we have that the length of each side are equal and the fourth side can accommodate any dimension of the other sides giving the maximum dimension of each side as 28/3

The dimensions of the deck are width = 28/3 m, breadth = 28/3 m

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s² = 98 m²

Therefore, s = √98 = 7·√2 m

Which gives the width = 7·√2 m and the breadth = 7·√2 m.

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