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natta225 [31]
3 years ago
7

What is meant by​ confounding?

Mathematics
1 answer:
ankoles [38]3 years ago
7 0

Answer:

a)

Step-by-step explanation:

In a study, if we want to measure of establish a relation between two variables, we say that there is a confounding variable when there is a third variable that is having an effect on our original two variables but this third variable wasn't originally measured in our study. Therefore our results are misleading because the relation between our two variables is being influenced by the confounding one.

This is why the correct answer would be the a) An explanatory variable has a great effect on a response variable. And this causes a misleading interpretation between the two variables.

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Se deposita 4000 soles a una tasa de interés del 0,8% quincenas .¿Que interes producirá en cinco quincenas?
katen-ka-za [31]

Answer:

Interes= 162,58

Step-by-step explanation:

Dada la siguiente información:

Se deposita 4000 soles a una tasa de interés del 0,8% quincenas

<u>Primero, debemos calcular el valor final de la inversión:</u>

VF= [VP*( 1 + i)^n]

VF= 4.000*(1,008^5)

VF= 4.162,58

<u>Para calcular el interés ganado en 5 quincenas, debemos usar la siguiente formula:</u>

Interes= 4.162,58  - 4.000

Interes= 162,58

5 0
2 years ago
Consider the transpose of Your matrix A, that is, the matrix whose first column is the first row of A, the second column is the
Zarrin [17]

Answer:The system could have no solution or n number of solution where n is the number of unknown in the n linear equations.

Step-by-step explanation:

To determine if solution exist or not, you test the equation for consistency.

A system is said to be consistent if the rank of a matrix (say B ) is equal to the rank of the matrix formed by adding the constant terms(in this case the zeros) as a third column to the matrix B.

Consider the following scenarios:

(1) For example:Given the matrix A=\left[\begin{array}{ccc}1&2\\3&4\end{array}\right], to transpose A, exchange rows with columns i.e take first column as first row and second column as second row as follows:

Let A transpose be B.

∵B=\left[\begin{array}{ccc}1&3\\2&4\end{array}\right]

the system Bx=0 can be represented in matrix form as:

\left[\begin{array}{ccc}1&3\\2&4\end{array}\right]\left[\begin{array}{ccc}x_{1} \\x_{2} \end{array}\right]=\left[\begin{array}{ccc}0\\0\end{array}\right] ................................eq(1)

Now, to determine the rank of B, we work the determinant of the maximum sub-square matrix of B. In this case, B is a 2 x 2 matrix, therefore, the maximum sub-square matrix of B is itself B. Hence,

|B|=(1*4)-(3*2)= 4-6 = -2 i.e, B is a non-singular matrix with rank of order (-2).

Again, adding the constant terms of equation 1(in this case zeros) as a third column to B, we have B_{0}:      

B_{0}=\left[\begin{array}{ccc}1&3&0\\4&2&0\end{array}\right]. The rank of B_{0} can be found by using the second column and third column pair as follows:

|B_{0}|=(3*0)-(0*2)=0 i.e, B_{0} is a singular matrix with rank of order 1.

Note: a matrix is singular if its determinant is = 0 and non-singular if it is \neq0.

Comparing the rank of both B and B_{0}, it is obvious that

Rank of B\neqRank of B_{0} since (-2)<1.

Therefore, we can conclude that equation(1) is <em>inconsistent and thus has no solution.     </em>

(2) If B=\left[\begin{array}{ccc}-4&5\\-8&10&\end{array}\right] is the transpose of matrix A=\left[\begin{array}{ccc}-4&-8\\5&10\end{array}\right], then

Then the equation Bx=0 is represented as:

\left[\begin{array}{ccc}-4&5\\-8&10&\end{array}\right]\left[\begin{array}{ccc}x_{1} \\x_{2} \end{array}\right]=\left[\begin{array}{ccc}0\\0\end{array}\right]..................................eq(2)

|B|= (-4*10)-(5*(-8))= -40+40 = 0  i.e B has a rank of order 1.

B_{0}=\left[\begin{array}{ccc}-4&5&0\\-8&10&0\end{array}\right],

|B_{0}|=(5*0)-(0*10)=0-0=0   i.e B_{0} has a rank of order 1.

we can therefor conclude that since

rank B=rank B_{0}=1,  equation(2) is <em>consistent</em> and has 2 solutions for the 2 unknown (X_{1} and X_{2}).

<u>Summary:</u>

  • Given an equation Bx=0, transform the set of linear equations into matrix form as shown in equations(1 and 2).
  • Determine the rank of both the coefficients matrix B and B_{0} which is formed by adding a column with the constant elements of the equation to the coefficient matrix.
  • If the rank of both matrix is same, then the equation is consistent and there exists n number of solutions(n is based on the number of unknown) but if they are not equal, then the equation is not consistent and there is no number of solution.
5 0
3 years ago
Simplify (2 (radical 5) - 4) (3 (radical 5) +2)
dem82 [27]
(2 \sqrt{5}-4 )(3 \sqrt{5}+2 )=\\2*3*5+2*2* \sqrt{5} -4*3* \sqrt{5}-4*2= \\ 30+4 \sqrt{5}-12 \sqrt{5}-8= \\ 22-8 \sqrt{5}
6 0
3 years ago
CAN SOMEONE HELP ME PLS!!!!
Anastaziya [24]

Step-by-step explanation:

the two opposites Angles of this quadrilateral are equal, again the angles should sum up to 360

t-9+t-91+t-16+t+25=360

4t=360-101

4t=259

t=64.75

8 0
2 years ago
(08.02)The ages of several trees in a neighborhood are shown below:
vesna_86 [32]
The answer is 12.4 :)


5 0
3 years ago
Read 2 more answers
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