D = 20
.....................................
Answer:
Explained
Step-by-step explanation:
Given that:
- A researcher is interested in determining whether a large aerospace firm is guilty of gender bias in setting wages.
According to the given info the difference in means test is too limited because it does not include the type of engineer, education level or experience. The gender with lower wages of might be reflected in the type of engineer or education level.
The research could be improved using additional data on the factors namely gender, education, education and the type of engineer.
Then, further it is recommended to construct a multiple regression where the dependent variable is a wage and the four factors are independent variables. The importance of the omited variable by the means of that the "difference in means" test in unsuitable for determining the gender bias in setting wages.
Answer:
The sum of money received by Ali, Carrie and Bryan is $ 740.
Step-by-step explanation:
At first we translate mathematically each sentence:
(i) <em>Ali, Carrie and Bryan received a sum of money. </em>
- Ali's money.
- Bryan's money.
- Carrie's money.
(ii) <em>Bryan's money was </em>
<em> of Ali's money</em>.
(1)
(iii) <em>The ratio of Ali's money to Carrie's money was 4 : 1</em>.
(2)
(iv) <em>Ali had $ 160 more than Bryan</em>.
(3)
After some algebraic handling, we have the following system of linear equations:
(1b)
(2b)
(3b)
The solution of the system is: 
, 
, 
The sum of money is:
The sum of money received by Ali, Carrie and Bryan is $ 740.
Answer:
Consider f: N → N defined by f(0)=0 and f(n)=n-1 for all n>0.
Step-by-step explanation:
First we will prove that f is surjective. Let y∈N be any natural number. Define x as the number x=y+1. Then x∈N, and f(x)=x-1=(y+1)-1=y. We conclude that f is surjective.
However, f is not injective. Take x1=0 and x2=1. Then x1≠x2 but f(x1)=0 and f(x2)=x2-1=1-1=0. We have shown that there are two natural numbers x1,x2 such that x1≠x2 but f(x1)=f(x2), that is, f is not injective.
Note:
If 0∉N in your definition of natural numbers, the same reasoning works with the function f: N → N defined by f(1)=1 and f(n)=n-1 for all n>1. The only difference is that you consider x1=1, x2=2 for the injectivity.
