Label each study as either an observational study, an experiment, or neither.

Many parents have expressed concerns that pertussis vaccinations will cause wheezing disorders or asthma in later life. In 2009 the Journal of the American Academy of Pediatrics published research by the Institute of Social and Preventive Medicine in Bern, Switzerland. The researchers wanted to determine if routine childhood vaccination against pertussis (whooping cough) was associated with subsequent development of childhood wheezing disorders and asthma. The researchers studied 6811 children from the general population born between 1993 and 1997 in Leicestershire, UK. From birth through 2003, they conducted repeated questionnaire surveys about wheeze and asthma and then linked the respiratory symptom data to independently collected vaccination data from the National Health Service database. Then the researchers compared wheeze and asthma incidents for children of three different levels of vaccination (complete, partial, and no vaccination). The analyses were based on 6,048 children with available vaccination records.

1. observational study2. an experiment3. neither

step-by-step explanation:

x^2 -12x + 36 + y^2 = 36

x^2 + y^2 = 12x

r^2 = 12rcos(theta)

r = 12 cos(theta)

a

step-by-step explanation:

when a number is between two straight lines it means the absolute value.

to find absolute value you need to know how many numbers is that number away from 0.

when finding absolute value the number will always come out positive

so absolute value of -3 is 3

absolute value of 3/2 is 3/2

absolute value of -2 is 2

absolute value of 3.5 is 3.5

absolute value of -1 is 1

now put these numbers in order:

a)   |-1|, |3/2|, |-2|, |-3|, |3.5|

5x + 3y = - 4

step-by-step explanation:

the equation of a line in standard form is

ax + by = c ( a is a positive integer and b, c are integers )

express the line first of all in slope- intercept form

y = mx + c ( m is the slope and c the y-intercept )

to calculate m use the gradient formula

m = ( y₂ - y₁ ) / ( x₂ - x₁ )

with (x₁, y₁ ) = (7, - 3) and (x₂, y₂ ) = (4, - 8)

m = = -

y = - x + c ← is the partial equation

to find c substitute either of the 2 points into the partial equation

using (4, - 8 ), then

- 8 = - + c ⇒ c = -

y = - x - ← in slope-intercept form

multiply all terms by 3 to eliminate the fractions

3y = - 5x - 4 ( add 5x to both sides )

5x + 3y = - 4 ← in standard form

answer: first option i.e. 'a' is correct.

step-by-step explanation:

since we have given that

number of minutes to wrap a small gift box = 4 minutes

we need to find the number of gifts to be wrapped in 5 minutes

since there is a direct variation, as the number of minutes will increase with   number of gifts to be wrapped.

so, let the number of gifts to be wrapped in 5 minutes be x.

so, it becomes,

hence, first option 'a'   is correct.