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.
Answer:
85%
Step-by-step explanation:
Monday:
200 x 0.70 = 140
200 - 140 = 60
Tuesday:
400 x ? = 60
400 x 0.85 = 340
400 - 340 = 60
Answer is (a.)
No it is not a function fails the vertical line test .