Answer:
The value of the test statistic is -2.64.
Step-by-step explanation:
The test statistic is:

In which X is the sample mean,
is the expected(claimed) mean,
is the standard deviation and n is the size of the sample.
An automobile manufacturer claims that its van has a 40.3 miles/gallon (MPG) rating.
This means that 
After testing 250 vans, they found a mean MPG of 39.9. Assume the standard deviation is known to be 2.4.
This means, respectively, that:

So



The value of the test statistic is -2.64.
First we have to work out everything inside the parentheses (according to PEMDAS):
9 × 2 = 18
4 - 2 = 2
Now, we can rewrite the expression:
4 + 18 ÷ 2 + 1
According to PEMDAS, we should complete the division in the middle first:
18 ÷ 2 = 9
Now we can rewrite the expression again:
4 + 9 + 1
And now it's as simple as just adding the three numbers together:
4 + 9 + 1 = 14
Your final answer is 14. :)
Answer:
15
Step-by-step explanation:
First: the homogeneous solutions: the characteristic equation is4r^2 - 4r - 3 = 0which has roots r = 3/2, -1/2 hence the homogeneous solution isy = c1.exp(-x/2) + c2.exp(3x/2)
next you need the general form for the guess for yp and that isyp = A1cos(2x) + A2sin(2x)
Now substitute that into the equation and solve for A1, A2.