Two variables of interest are the dependent variable, infant birth weight in ounces (bwght), and an explanatory variable, average number of cigarettes the mother smoked per day during pregnancy (cigs). the following simple regression was estimated using data on n = 1,388 births, bwght = 119.77 − 0.514 cigs
(i) what is the predicted birth weight when cigs = 0? what about when cigs = 20? comment on the difference.
(ii) does this simple regression necessarily capture a causal relationship between the child’s birth weight and the mother’s smoking habits? explain.
(iii) to predict a birth weight of 125 ounces, what would cigs have to be?

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional

step-by-step explanation:

given expression is .

now we need to simplify the given expression .

we know that square root is equivalent to the power 1/2. so that means we can take half of the exponents to get the square root of given expression.

expanding that will give a very very large number so let's keep answer in exponent form.

step by step explanation: when u removing the parentheses and combined them that would be : x+3y-x-y=2y

answer: it depends on what the tax percentage