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Aliun [14]
3 years ago
11

Accident rate data y1, ...., y12 were collected over 12 consecutive years t=1,2,...12. At over 12 consecutive years t = 1,2,...,

12. At the end of the 6th year, a change in safety regulations occured. FOr each of the following situations, set up a linear model of the form y=XB+E. Define X and B appropriately.
a. The accident rate y is a linear function of t with the new safety regulations having no effect.

b. The accident rate y is a quadratic function of t with the new regulations having no effect.

c. The accident rate y is a linear function of t. The slope for t>= 7 is the same as for t<7. However there is a discrete jump for t=7.

d. The accident rate y is a linear function of t. After t=7, the slope changes, with the two lines intersecting at t=7.
Mathematics
1 answer:
e-lub [12.9K]3 years ago
4 0

Answer:

The correct option is;

The accident rate is a linear model function of t. After t = 7, the slope changes, with the two lines intersecting at t = 7

Step-by-step explanation:

The given parameters are;

Accident rate data = y₁, y₂, y₃, y₄, y₅, y₆, y₇, y₈, y₉, y₁₀, y₁₁, y₁₂

Time at which data was recorded = t₁, t₂, t₃, t₄, t₅, t₆, t₇, t₈, t₉, t₁₀, t₁₁, t₁₂

Accident rate equation is a linear model given as follows;

y = X·B + E

Where:

y = Accident rate

X = Slope of linear model

B = Year

E = y intercept of model

At the end of the 6th year, a change in a regulation that affects safety, hence accident rate occurred given as follows;

Before the change in safety regulations occurred for year t < 7 y₁ = X₁B + E₁

After the change in safety regulations occurred for year t < 7 y₂ = X₂B + E₂

Therefore the slope changes from X₁ to X₂ after t = 7 with the second linear model starting from the end of the first linear model making the two lines intersect at t = 7 (the beginning of year 7)

Hence the correct option is that "The accident rate is a linear model function of t. After t = 7, the slope changes, with the two lines intersecting at t = 7."

You might be interested in
Find four distinct complex numbers (which are neither purely imaginary nor purely real) such that each has an absolute value of
Luda [366]

Answer:

  • 0.5 + 2.985i
  • 1 + 2.828i
  • 1.5 + 2.598i
  • 2 + 2.236i

Explanation:

Complex numbers have the general form a + bi, where a is the real part and b is the imaginary part.

Since, the numbers are neither purely imaginary nor purely real a ≠ 0 and b ≠ 0.

The absolute value of a complex number is its distance to the origin (0,0), so you use Pythagorean theorem to calculate the absolute value. Calling it |C|, that is:

  • |C| = \sqrt{a^2+b^2}

Then, the work consists in finding pairs (a,b) for which:

  • \sqrt{a^2+b^2}=3

You can do it by setting any arbitrary value less than 3 to a or b and solving for the other:

\sqrt{a^2+b^2}=3\\ \\ a^2+b^2=3^2\\ \\ a^2=9-b^2\\ \\ a=\sqrt{9-b^2}

I will use b =0.5, b = 1, b = 1.5, b = 2

b=0.5;a=\sqrt{9-0.5^2}=2.958\\ \\b=1;a=\sqrt{9-1^2}=2.828\\ \\b=1.5;a=\sqrt{9-1.5^2}=2.598\\ \\b=2;a=\sqrt{9-2^2}=2.236

Then, four distinct complex numbers that have an absolute value of 3 are:

  • 0.5 + 2.985i
  • 1 + 2.828i
  • 1.5 + 2.598i
  • 2 + 2.236i
4 0
3 years ago
A+b=180<br> A=-2x+115<br> B=-6x+169<br> What is the value of B?
natulia [17]
The answer is:  " 91 " .   
___________________________________________________
                    →    " B = 91 " .
__________________________________________________ 

Explanation:
__________________________________________________
Given:  
__________________________________________________
    "  A +  B = 180 " ;

  "A =  -2x + 115 " ;   ↔  A =  115 − 2x ;  

  "B = - 6x + 169 " ;  ↔  B = 169 − 6x ;  
_____________________________________________________
METHOD 1)
_____________________________________________________
Solve for "x" ; and then plug the solved value for "x" into the expression given for "B" ; to  solve for "B"
_____________________________________________________

(115 − 2x) + (169 − 6x) = 

  115 − 2x + 169 − 6x = ?

→ Combine the "like terms" ;  as follows:

      + 115 + 169 = + 284 ; 

 − 2x − 6x = − 8x ; 
_________________________________________________________
And rewrite as:

 " − 8x + 284 " ; 
_________________________________________________________
   →  " - 8x + 284 = 180 " ; 

Subtract:  "284" from each side of the equation:

  →  "  - 8x + 284 − 284 = 180 − 284 " ; 

to get:

 →  " -8x = -104 ; 

Divide EACH SIDE of the equation by "-8 " ; 
    to isolate "x" on one side of the equation; & to solve for "x" ; 

→ -8x / -8 = -104/-8 ; 

→  x = 13
__________________________________________________________
Now, to find the value of "B" :
__________________________________________________________
  "B = - 6x + 169 " ;  ↔  B = 169 − 6x ;  

↔  B = 169 − 6x ;  

         = 169 − 6(13) ;   ===========> Plug in our "solved value, "13",  for "x" ;

         = 169 − (78) ; 

         = 91 ;

   B   = " 91 " .
__________________________________________________
The answer is:  " 91 " . 
____________________________________________________
     →     " B = 91 " . 
____________________________________________________
Now;  let us check our answer:
____________________________________________________
               →   A + B = 180 ;  
____________________________________________________
Plug in our "solved answer" ; which is "91", for "B" ;  as follows:
________________________________________________________

→  A + 91 = ? 180? ;  

↔  A = ? 180 − 91 ? ; 

→  A = ?  -89 ?  Yes!
________________________________________________________
→  " A =  -2x + 115 " ;   ↔  A =  115 − 2x ;  

Plug in our solved value for "x"; which is: "13" ; 

" A = 115 − 2x " ; 

→  A = ? 115 − 2(13) ? ;

→  A = ? 115 − (26) ? ; 

→  A = ? 29 ? Yes!
_________________________________________________ 
METHOD 2)
_________________________________________________
Given:  
__________________________________________________
    "  A +  B = 180 " ;

  "A =  -2x + 115 " ;   ↔  A =  115 − 2x ;  

  "B = - 6x + 169 " ;  ↔  B = 169 − 6x ; 

→  Solve for the value of "B" :
_______________________________________________________
 A + B = 180 ;  

→ B = 180 − A ; 

→ B = 180 − (115 − 2x) ; 

→ B = 180 − 1(115 − 2x) ;  ==========> {Note the "implied value of "1" } ; 
__________________________________________________________
Note the "distributive property" of multiplication:__________________________________________________  a(b + c)  = ab +  ac ;  <u><em>AND</em></u>:
  a(b − c)  = ab − ac .________________________________________________________
Let us examine the following part of the problem:
________________________________________________________
              →      " − 1(115 − 2x)  " ; 
________________________________________________________

→  "  − 1(115 − 2x) " = (-1 * 115) − (-1 * 2x) ;

                                =  -115 − (-2x) ;
                         
                                =  -115  +  2x ;        
________________________________________________________
So we can bring down the:  " {"B = 180 " ...}"  portion ; 

→and rewrite:
_____________________________________________________

→  B = 180 − 115 + 2x ; 

→  B = 65 + 2x ; 
_____________________________________________________
Now;  given:   "B = - 6x + 169 " ;  ↔  B = 169 − 6x ; 

→ " B =  169 − 6x  =  65 + 2x " ; 
______________________________________________________
→  " 169 − 6x  =  65 + 2x "

Subtract "65" from each side of the equation;  & Subtract "2x" from each side of the equation:

→  169 − 6x − 65 − 2x  =  65 + 2x − 65 − 2x ; 

to get:

→   " - 8x + 104 = 0 " ;
 
Subtract "104" from each side of the equation:

→   " - 8x + 104 − 104 = 0 − 104 " ;

to get: 

→   " - 8x = - 104 ;

Divide each side of the equation by "-8" ; 
   to isolate "x" on one side of the equation; & to solve for "x" ; 

→  -8x / -8  = -104 / -8 ; 

to get:

→  x =  13 ; 
______________________________________________________

Now, let us solve for:  " B " ;  → {for which this very question/problem asks!} ; 

→  B = 65 + 2x ;  

Plug in our solved value, " 13 ",  for "x" ; 

→ B = 65 + 2(13) ; 

        = 65 + (26) ;  

→ B =  " 91 " .
_______________________________________________________
Also, check our answer:
_______________________________________________________
Given:  "B = - 6x + 169 " ;   ↔  B = 169 − 6x = 91 ; 

When "x  = 13 " ; does: " B = 91 " ? 

→ Plug in our "solved value" of " 13 " for "x" ;

      → to see if:  "B = 91" ; (when "x = 13") ;

→  B = 169 − 6x ; 

         = 169 − 6(13) ; 

         = 169 − (78)______________________________________________________
→ B = " 91 " . 
______________________________________________________
6 0
3 years ago
Sara works 40 hours per week and earns $660. Which graph shows the unit rate for this situation?
coldgirl [10]

Answer: $16.5/hour

Step-by-step explanation:

The unit rate is the relationship between y and x if x = 1

660/40 = 16.5

That means, if x = 1, y = 16.5

Therefore, <u>$16.5/hour</u>

<u></u>

3 0
2 years ago
2² + {[1 x (5 - 2)] x 3
alexandr1967 [171]

Answer:

The answer is 13

Step-by-step explanation:

Hope this helps :)

5 0
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Annie buys some greeting cards. Each card costs $1.75. She pays with a twenty dollar bill.
zaharov [31]

Answer:

Step-by-step explanation:

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