1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
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 

You might be interested in
Label x-intercepts, vertex and axis of symmetry for f(x) = (x+3)(x-5)
Lera25 [3.4K]
X intercepts are -3 and 5
7 0
3 years ago
Miss Barton and three neighbors purchase a snowblower to share. If the snow blower cost for 439.20, describe how you can estimat
faust18 [17]
Each person will have to pay 700 dollars
5 0
3 years ago
a person is standing on top of a smaller building looking across the street at a taller building, which is 260 feet away horizon
Anuta_ua [19.1K]

The height of the smaller building is <u>94.63 feet</u>, computed using the trigonometric ratios.

In the question, we take AB to be the taller building, where A is its top and B is its base, CD to be the shorter building, where C is its top and D is its base, and CE to be the perpendicular from C to AB.

Given that the horizontal distance between the two buildings is 260 feet, we can say that BC = CE = 260 feet.

The angle of elevation from the top of the shorter building to the top of the taller building is 30°, that is, ∠ECA = 30°.

The angle of depression from the top of the shorter building to the base of the taller building is 20°, that is, ∠ECB = 20°.

When ∠ECB = 20°, then ∠CBD = 20°, as they are alternate angles.

We are asked to find the height of the shorter building, that is, we are asked to find CD.

In ΔCBD,

tan ∠CBD = CD/BD {perpendicular/base},

or, tan 20° = CD/260,

or, CD = 260*tan 20° = 260*0.36397023426 {∵ tan 20° = 0.36397023426},

or, CD = 94.6322609092.

Therefore, the height of the smaller building is <u>94.63 feet</u>, computed using the trigonometric ratios.

Learn more about heights and distances at

brainly.com/question/2004882

#SPJ4

7 0
2 years ago
What is the rate of change for y=2x+10
Tanzania [10]

Answer:

its 2  

The general rate of change can be found by using the difference quotient formula. To find the average rate of change over an interval, enter a function with an interval

8 0
3 years ago
How Do I To Study Effectively?
dangina [55]
Studying effectively is more harder than it sounds, but the best way to get in the zone in finding what things you prefer. Do you like silence or do you like to listen to music? Another thing when looking forward to studying is determining what you want to accomplish in each study session. To ensure you are studying your brain to the max is making flash cards and testing your own limit’s.
4 0
3 years ago
Read 2 more answers
Other questions:
  • Find the slope of the line contain the given pair of points (-6,4) and (1,0)
    11·2 answers
  • My teacher says everything is there to answer this question but I don't know. Someone please explain.
    12·1 answer
  • 3. What is the area of the circle shown below?<br> Diameter:<br> 28 inches<br> Pi=3.14
    13·2 answers
  • You swim in a 100-meter race. Your best time is 59.48 seconds. You want to swim the race in 51.55 seconds. How much will you nee
    9·1 answer
  • The office worker can stamp 25 letters per minute.
    9·2 answers
  • What is the value of x?<br><br> Enter your answer in the box.<br><br> __ ft
    15·2 answers
  • Which ratio is equivalent to 4 to 24
    10·2 answers
  • X intercept of x+y=5
    14·1 answer
  • What is 1 1/2 - 3 5/7?
    15·1 answer
  • You enter a room. 2 dogs, 4 horses, one giraffe, and a duck are laying on a bed. 3 chicken are flying over a chair. How many leg
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!