Answer:
1\2.
Step-by-step explanation:
change in y over change in x. so 13 - 11 over 6 - 2. 2/4 --.> 1\2.
Answer:
The required confidence inteval = 94.9%.
Step-by-step explanation:
Confidence interval: Mean ± Margin of error
Given: A confidence interval for the true mean diameter of all oak trees in the neighbourhood is calculated to be (36.191, 42.969).
i.e. Mean + Margin of error = 42.969 (i)
Mean - Margin of error = 36.191 (ii)
Adding (i) and (ii), we get

Margin of error = 42.969-39.58 [from (i)]
= 3.389
Margin of error = 
here n= 25 
i.e.

Using excel function 1-TDIST.2T(2.054,24)
The required confidence inteval = 94.9%.
Answer:
It would be -7
Step-by-step explanation:
The 12 is negative, so instead of adding, you would subtract 5.
Answer:
Part A) see the explanation
Part B) 
Step-by-step explanation:
Part A)
we know that
A relationship between two variables, x, and C, represent a proportional variation if it can be expressed in the form
or 
Let
C ---> is the total cost (represent the output or dependent variable)
x ----> is the number of books (represent the input or independent variable)
In this problem
we have a proportional relationship between the variables x and C
Part B) we know that
The linear equation is given by

The constant of proportionality k is the same that the slope or unit rate of the linear equation
In this problem the constant k is given

so

For x=12 books
substitute in the equation and solve for C

In function notation
