FIND THE DIFFERENCE (SLOPE)
FORMULA: (y2-y1)/(x2-x1)
the numbers after the 'x' or 'y' in the formula depict which value to use.
y2 = 26
y1 = 15
x2 = 3
x1 = 2
PLUG IN. (26-15 = 11) delta y
(3-2 = 1) delta x
delta = difference, it's just a fancy math term.
*NOTE: don't use the division sign in literal terms, you are trying to find the slope (which is usually left as a fraction)
slope = 11/1 MEANING that for every rise of 11, the line runs 1
rise = y axis
run = x axis
SLOPE INTERCEPT FORM (FORMULA)
y=mx+b
where Y shows the function and does not serve as a variable value/purpose
m=slope
x= (alike Y) also does not serve as a true value/ purpose
b= y-intercept
Y=11x+b
when x = 0, y = ? (Y INTERCEPT)
y intercept = -7
since this function had two points that so eagerly boasted their close proximity to the y axis, I simply subtracted 1 from the closer of the two (to x=0) and then subtracted 11 the same amount of times from the y value/
Since the slope is 11, to find the y intercept, you must set x = 0.
for every decrease of 1 to the x value, the y value will decrease by 11.
*NOTE: This relationship is not always prominent, sometimes... The slope is negative, or is even represented by a fraction. In which an inverse relationship would be more suitable than a direct one, causing the x and y values to move in opposite directions of the other. Be careful when dealing with improper fractions as slopes, you must heed extra warning to identify whether the fraction is greater or less than 1.
NEW FUNCTION.... Y=11x-7
Test it out....
The confidence interval would be (10.44, 12.16). This means that if we take repeated samples, the true mean lies in 90% of these intervals.
To find the confidence interval, we use:
We first find the z-value associated with this. To do this:
Convert 90% to a decimal: 90% = 90/100 = 0.9
Subtract from 1: 1-0.9 = 0.1
Divide by 2: 0.1/2 = 0.05
Subtract from 1: 1-0.05 = 0.95
Using a z-table (http://www.z-table.com) we see that this is directly between two z-scores, 1.64 and 1.65; we will use 1.645:
If x is meant to equal the square footage of the house then we can substitute 1900 for x.
y = 0.074(1900) + 50.48
y = 140.6 + 50.48
y = 191.08
If y is meant to equal square footage then substitute 1900 for y.
y = 0.074x + 50.48
1900 = 0.074x + 50.48
1900 - 50.48 = 0.074x
1849.52 = 0.074x
1849.52/0.074 = x
24,993. 51 = x
X=71
A right triangle has an angel of 90 degrees
So 13+6=22
90-19=71
Therefore X=71