Let
be the random variable for the number of marks a given student receives on the exam.
10% of students obtain more than 75 marks, so

where
follows a standard normal distribution. The critical value for an upper-tail probability of 10% is

where
denotes the CDF of
, and
denotes the inverse CDF. We have

Similarly, because 20% of students obtain less than 40 marks, we have

so that

Then
are such that


and we find

Answer:
Y = 7.60X + 1246.67
Step-by-step explanation:
Given the data:
Production Volume (units) Total Cost ($)
400 4000
450 5000
550 5400
600 5900
700 6400
750 7000
Using technology, the linear regression calculator, the regression model obtained by fitting the data is :
Y = 7.60X + 1246.67 ; which is the model giving the relationship between Production volume, x and total cost, y.
Slope = 7.60
Intercept = 1246.67
1/9 because i you plug in two of the points into y2 -y1 over x2 -x1 thats what you get.
If you would like to solve the equation x^2 + 12 * x = -11, you can calculate this using the following steps:
x^2 + 12 * x = -11
<span>x^2 + 12 * x + 11 = 0
</span>(x + 1) * (x + 11) = 0
1. x = - 1
2. x = - 11
The correct result would be x = - 1, or x = - 11.