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Dmitriy789 [7]
3 years ago
14

A medical researcher studies the correlation between the number of hours spent at office jobs and the incidence of chronic back

ache. Which statement BEST describes why the investigation is an observational study?
A) The researcher does not use a control group.
B) The researcher does not intervene to vary conditions.
C) It is not possible to obtain a random sample of office workers.
D) It is not possible to establish a cause-effect relation between the variables.
Mathematics
1 answer:
Sati [7]3 years ago
5 0
The answer for this question is C 

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Maximizing revenue. Edwards University wants to determine what price to charge for tickets to football games. At $18 per ticket,
Papessa [141]

Answer:

New price is $12.75

New attendance is 57500

Step-by-step explanation:

For starters, we use the relation.

18 - 3x

Since we don't know the number of times we're expected to deduct $3 from the price.

Again, we have 40000 + 10000x on another hand. Question says to add 10000 people everytime $3 is deducted.

Since (40000 + 10000x) is the number of people, we multiply it by $4.50, the average amount each person spends is then gotten to be

(18 - 3x) (40000 + 10000x) + (40000 + 10000x) (4.5) = 0

Expanding the bracket, we have

[720000 + 60000x - 30000x²] + [180000 + 45000x] = 0, solving further, we have

900000 + 105000x - 30000x² = 0 or

-30000x² + 105000x + 900000 = 0

Then, we find the maximum of a quadratic, by finding the axis of symmetry. Use x = -b/2a

x = -105000 / 2 * -30000

x = -105000 / -60000

x = 1.75

From our earlier equations, the new price then is

18 - 3(1.75) = 18 - 5.25 = $12.75

The new attendance also is

40000 + 10000(1.75) =

40000 + 17500 = 57500

7 0
3 years ago
What is 1 and 1/6 minus 7/12 ?
Damm [24]
1 \frac{1}{6} -  \frac{7}{12} \\ 
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 \\  \frac{14}{12} -  \frac{7}{12}= \frac{7}{12} \\ 
 \\ Solution: \frac{7}{12} 

7 0
4 years ago
Helpp me answer this question and explain
Ganezh [65]
The answer is A, you can tell because if you multiply 4 by the numbers inside the parentheses you’ll get =12+24..hope that helped :)
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3 years ago
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sveta [45]
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2 years ago
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dusya [7]

Step-by-step explanation:

D. Graph D the answer is D

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