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Probability-and-statistics/364479: 1. If the random variable z is the standard normal score, is it true that P(-3 < z < 3) > 1? Why or why not?
2. Givent a binomial distribution with n = 29 and p = 0.83, would the normal distribution provide a reasonable approximation? Why or why not?
3. Find the area under the standard normal curve for the following: a). P(z < -0.25) b). P(0.55 < z < 0) c.) P(-1.91 < z < 1.06) 1 solutions
Answer 259884 by Fombitz(13828) on 2010-11-01 10:11:25 (Show Source):
You can put this solution on YOUR website!1)

So  can never be greater than  .
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2)
The binomial distribution is approximated by a normal distribution for any fixed  (even if  is small) as  is taken to infinity.
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3) 
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Length-and-distance/364466: Hi All,
Having difficulty with this particular problem on a task sheet, any help would be greatly appreciated.
Given a=i+3j-k and b=2i+j-k, find a.b and the cosine of the angle Theta between the vectors
b) Given a= 3i+j-2k and b= -6i-2j+4k find a.b and the angle theta between vectors
Finaly c) For what value of alpha will the vectors a+5i+2j+3k and b=2i+alphaj+alphak be perpendicular?
Many thanks in advance for any help.
Mike 1 solutions
Answer 259882 by Fombitz(13828) on 2010-11-01 09:56:25 (Show Source):
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Mixture_Word_Problems/364472: How many gallons of antifreeze do I need to keep 450 gallons of water from freezing? 1 solutions
Answer 259878 by Fombitz(13828) on 2010-11-01 09:42:16 (Show Source):
You can put this solution on YOUR website!Depends on the type of antifreeze (alcohol, ethylene glycol, etc.). However you should check with the manufacturer of the specific brand to see the mix for the temperature you're protecting against.
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Graphs/364341: graph the inequality: x-y>-5 1 solutions
Answer 259872 by Fombitz(13828) on 2010-11-01 09:27:22 (Show Source):
You can put this solution on YOUR website!
Graph the line,

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Now choose a point not on the line.
Test the inequality.
If the inequality is satisfied, shade the region containing the point.
If not, shade the region not containing the point.
Choose (  ,  ) for convenience.

True, shade the region containing (  ,  ).
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Matrices-and-determiminant/364426: Solve the matrix equation
-2x+3■(2&-8@-4&2)=■(4&-6@2&-8)
I am not sure how to type matrices in here.
Please help, I am trying to help my son with his algebra and neither one of us understands how to do this. Could you please explain in step by step instructions. Thank You. 1 solutions
Answer 259858 by Fombitz(13828) on 2010-11-01 08:53:33 (Show Source):
You can put this solution on YOUR website!You can list them in order, like,
[A] is a 2x2 matrix [A]=(1 2 3 4) for [A]= 
[B] is a 3x3 matrix [B]=(9 8 7 6 5 4 3 2 1) for [B]= 
[C] is a 3x1 matrix [C]=(x y z) for [C]= 
Then solve,
4[B][C]-12[C]
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Probability-and-statistics/364428: For the least-squares line y^ = 2 − 2x, what is the value of the slope?
When x changes by 1 unit, by how much does y^ change?
Answer: I know y^ decreases but I cannot figure out how much. 1 solutions
Answer 259854 by Fombitz(13828) on 2010-11-01 08:49:18 (Show Source):
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Exponential-and-logarithmic-functions/364455: Hi, I'm looking for some serious help. If anyone could help me, by showing all the steps you utilized to get the answer, I would greatly appreciate it.
Section 12.1, #5, pg 826
Directions: Approximate each number using a calculator. Round your answer to three decimal places.
4^(-1.5)
1 solutions
Answer 259849 by Fombitz(13828) on 2010-11-01 08:45:48 (Show Source):
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Linear-systems/364435: Find the slope-intercept equation of the line parallel to the line 12x + 3y = 15 and containing the point (–1, 7). Explain and show work. 1 solutions
Answer 259848 by Fombitz(13828) on 2010-11-01 08:43:14 (Show Source):
You can put this solution on YOUR website!First find the slope of the first line by converting to slope-intercept form,  .

Parallel lines have identical slopes,

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Use the point (-1,7) to solve for  .

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Linear-systems/364436: Given x=
x+7
_______
x^(2)-9
determine the domain.
A. All real numbers except –3 and 3
B. All real numbers except –7 and 3
C. All real numbers except –7, –3, and 3
D. All real numbers except 0
1 solutions
Answer 259847 by Fombitz(13828) on 2010-11-01 08:39:39 (Show Source):
You can put this solution on YOUR website!I think you mean 
The domain is all numbers except those that make the denominator equal zero since division by zero is undefined.
A) All except  and  .
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Inequalities/364449: The inequality x^2 - 2x + 1 ≤ 0 has
A) no solutions
B) a set of solutions
C) 1 solution only
D) 2 solutions only
E) 3 solutions only 1 solutions
Answer 259845 by Fombitz(13828) on 2010-11-01 08:38:09 (Show Source):
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Linear-systems/364439: The points (2, 5) and (4, –1) are endpoints of the diameter of a circle.
(a) State the center of the circle.
(b) Find the length of the radius of the circle. (Note that this is a distance.) Show work.
(c) State the equation of the circle (in standard form). Note that you know the center and the radius from the previous parts.
1 solutions
Answer 259844 by Fombitz(13828) on 2010-11-01 08:34:33 (Show Source):
You can put this solution on YOUR website!a)Use the midpoint formula,

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b) Use the distance formula,

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c) Use the equation of a circle centered at (h,k) with radius R.

Expand the x and y terms to get to standard form.
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Probability-and-statistics/364443: probability of Ann passing her math test is 90%. The probability she passes her English test is 80%. The probability she passes her Chemistry test is 70%. What is the probability she passes all three tests? 1 solutions
Answer 259841 by Fombitz(13828) on 2010-11-01 08:28:20 (Show Source):
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Probability-and-statistics/364333: Automobiles arrive at the Elkhart exit of the Indiana Toll Road at the rate of two per minute. The distribution of arrivals approximates a Poisson distribution.
1. What is the probability that no automobiles arrive in a particular minute?
2. What is the probability that at least one automobile arrives during a particular minute?
1 solutions
Answer 259769 by Fombitz(13828) on 2010-10-31 21:08:12 (Show Source):
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