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xenn [34]
3 years ago
10

Determine what type of observational study is described. Explain. Researchers wanted to determine whether there was an associati

on between city driving and stomach ulcers. They selected a sample of 900 young adults and followed them for a ​twenty-year period. At the start of the study none of the participants was suffering from a stomach ulcer. Each person kept track of the number of hours per week they spent driving in city traffic. At the end of the study each participant underwent tests to determine whether they were suffering from a stomach ulcer. The researchers analyzed the results to determine whether there was an association between city driving and stomach ulcers.
Mathematics
1 answer:
Karo-lina-s [1.5K]3 years ago
8 0

Answer: Structured Observation

Step-by-step explanation:

The observation is so named because, the problem has be defined and the behavioural pattern has to be measured, and the method of observation is also known to the participant who weekly turn in their statistics.

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tigry1 [53]

Answer:

32pi

Step-by-step explanation:

6 0
3 years ago
PLEASE HELP ASAP!!!!
yanalaym [24]

Answer:

a = -4

b = 3

c = 6

Step-by-step explanation:

x^2 + 8x = 38

We take the coefficient of the x term

Divide by 2 and then square it

8/2 =4

4^2 = 16

Add 16 to both sides

x^2 +8x + 16 = 38 + 16

x^2 +8x +16 = 54

Take b/2 and use it in the the (x+b/2)^2

(x+4)^2 = 54

Take the square root of each side

sqrt((x+4)^2) = ± sqrt(54)

x+4 =  ± sqrt(54)

Subtract 4 from each side

x+4-4 = -4  ± sqrt(54)

x = -4  ± sqrt(54)

Simplify the square root

x = -4  ± sqrt(9*6)

x = -4 ± sqrt(9) sqrt(6)

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8 0
3 years ago
I need help with this one because I got my answers wrong
cluponka [151]
40+60+y=180
y=180-100
y=80

A triangle is 180° so you add all the numbers available in the trianle and minus it with 180 to see what is left from the 180 and that will be the inner angle answer

X=180-80=100

A straight line is also 180° so if u minused one side which in our case is 80 u will get the rest which is the outer angle
7 0
3 years ago
Matt and Mark went to El Rodeo to have some dinner. Matt ordered 3 tacos and 2 enchiladas, which cost him $4.93. Mark ordered 2
lord [1]

Answer:

The cost of one taco is $0.87 and the cost of one enchilada is $1.16

Step-by-step explanation:

Let the cost of tacos be X

and cost of enchiladas be y

So, by using given data, we have following equations

3X + 2Y = 4.93             (1)

2X + 4Y = 6.38             (2)

So, first multiply 1st equation by 2 and 2nd equation by 3, then subtracting 1st equation by 2nd.

= 2 × ( 3X + 2Y = 4.93)       (1)

= 3 × (2X + 4Y = 6.38)        (2)

= - (6X + 4Y = 9.86)              (1)

= 6X + 12y = 19.14            (2)

= 8Y = 9.28

Y = 9.28 ÷ 8 = 1.16

By putting the value of Y in equation 1, we get

3X + 2(1.16) = 4.93

3X + 2.32 = 4.93

X = 2.61 ÷ 3 = 0.87

Hence, the cost of one taco is $0.87 and the cost of one enchilada is $1.16.

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