Answer:
C. We want to determine if there is significant evidence that the mean strength of welds exceeds 100 lb/in2. The current hypotheses correctly place the burden of proof on those who wish to assert that the specification is satisfied.
Step-by-step explanation:
Given
Required
State why it is preferred to
From the question, we understand that the initial test is the force required to break the weld.
This represents the null hypothesis
Because the required force can not be less than the strength of the weld (it must match the force keeping the weld), the null hypothesis is represented as:
Reading the question further;
The specification requires that the mean strength should exceed 100
In inequalities, exceeds means greater than, and it is represented with >
So, the null hypothesis is rightly represented as:
Hence: (c) is true
She should invest $30000 in the 9% fund and $10000 in the 13% fund.
<u><em>Explanation</em></u>
Suppose, the amount of investment at 9% rate is dollar.
As the total amount of investment is $40000 , so the investment at 13% rate will be:
So, the amount of earnings per year from 9% fund dollar
and the amount of earnings per year from 13% fund dollar.
Given that, the <u>total earnings per year is $4000</u>. So the equation will be......
So, the amount of investment at 9% fund is $30000 and the amount of investment at 13% fund = ($40000- $30000)= $10000
Well, do algebra first. So, x+2/X+2 wouldn't that cancel out to 1.... So f(x) = 1 and no need for a calculator!
Hope this helps!