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j-astron
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j-astron
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01-10-2018
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11-15-2018
12:02 PM
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11-13-2018,
03:04 PM
j-astron
started a thread
Covariance of the Sample Mean of Two Random Vectors
in
Probability / Statistics
Hello everyone, This is not homework, it's a real problem I encountered in data analysis. I'll try to state the problem as clearly as possible,...
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0 replies | 145 view(s)
11-13-2018,
02:11 PM
j-astron
replied to a thread
Average and standard deviation of the bending moment in the beams
in
Probability / Statistics
Hi Erwin1998, welcome to the forum. It's been a while since I've had to think about bending moment (Introductory Mechanics, basically). But having...
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3 replies | 224 view(s)
11-12-2018,
10:30 PM
j-astron
replied to a thread
Probability of type 1 and type 2 errors: Add 50 to each value in this list, and...
in
Probability / Statistics
Yes No. Again, you need to understand what the Z-table is telling you. This tells you that the probability of being this far below the mean...
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4 replies | 298 view(s)
11-12-2018,
10:26 PM
j-astron
replied to a thread
Probability of type 1 and type 2 errors: Add 50 to each value in this list, and...
in
Probability / Statistics
Yeah, but you need to be aware of what the "positive Z-table" is telling you. It's telling you the probability of being less than or equal to the...
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4 replies | 298 view(s)
11-12-2018,
12:32 AM
j-astron
replied to a thread
Probability of type 1 and type 2 errors: Add 50 to each value in this list, and...
in
Probability / Statistics
Hi StatsBeginner, Let's consider the first case first: You're looking for evidence that value 94 is unusual somehow. In this case, that means...
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4 replies | 298 view(s)
11-04-2018,
02:54 PM
j-astron
replied to a thread
Universe Expansion Calculation: max initial dist from source that can be visited...
in
Intermediate/Advanced Algebra
With all of the above information in mind, we are finally in a position to answer the question of what is the distance that a photon, leaving...
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11 replies | 406 view(s)
11-04-2018,
02:53 PM
j-astron
replied to a thread
Universe Expansion Calculation: max initial dist from source that can be visited...
in
Intermediate/Advanced Algebra
Hi sinx. The answer to this is not short, but ok , here goes: sinx, your calculation doesn't work because you have treated the 68k number as being...
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11 replies | 406 view(s)
11-04-2018,
02:20 PM
j-astron
replied to a thread
Universe Expansion Calculation: max initial dist from source that can be visited...
in
Intermediate/Advanced Algebra
As far as I can tell, the OP isn't asking a question, just making a statement. Yes, it is an interesting and perhaps sobering result that a good...
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11 replies | 406 view(s)
10-27-2018,
05:38 PM
j-astron
replied to a thread
Uniform distribution & expected payment for internet-service contract
in
Probability / Statistics
Could you just read a bit more carefully please? I always quoted which post I was referring to. I already replied telling you that I thought 9.2 was...
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13 replies | 471 view(s)
10-23-2018,
09:16 PM
j-astron
replied to a thread
Uniform distribution & expected payment for internet-service contract
in
Probability / Statistics
This seems right to me:...
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13 replies | 471 view(s)
10-23-2018,
09:00 PM
j-astron
replied to a thread
Uniform distribution & expected payment for internet-service contract
in
Probability / Statistics
Yes, something is dramatically wrong, unfortunately. You're treating the random variable X as though it were discrete, i.e. it could only take on...
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13 replies | 471 view(s)
10-23-2018,
08:49 PM
j-astron
replied to a thread
Uniform distribution & expected payment for internet-service contract
in
Probability / Statistics
No. This doesn't make sense. Nothing is discrete here. What if your usage had been BETWEEN 3 GB and 4 GB? You'd be in the regime where you were...
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13 replies | 471 view(s)
10-23-2018,
06:15 PM
j-astron
replied to a thread
Struggling: eed to know the total xp required to reach 1000
in
Intermediate/Advanced Algebra
Let's call the next level you want to get to L (so the current level is L-1), and the number of experience points (XP) needed to get to that next...
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4 replies | 481 view(s)
10-19-2018,
12:15 PM
j-astron
replied to a thread
Representing a view of a 3D sphere as a 2D circle?
in
Geometry and Trig
Hey @Fillipuster: Can you explain what you mean by "precision?" Any raster-graphic is going to have finite precision, because it has pixels of...
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3 replies | 207 view(s)
10-18-2018,
02:05 PM
j-astron
replied to a thread
Uniform distribution & expected payment for internet-service contract
in
Probability / Statistics
Also, for the first Internet plan, I actually get $12.80 as the expected payment using three methods: 1) pencil and paper calculation 2) Sticking...
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13 replies | 471 view(s)
10-18-2018,
01:42 PM
j-astron
replied to a thread
Uniform distribution & expected payment for internet-service contract
in
Probability / Statistics
Hi Amazon1234, Remember that this random variable is not discrete, it's continuous. Because you aren't limited to just using an integer number of...
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13 replies | 471 view(s)
10-18-2018,
10:51 AM
j-astron
replied to a thread
Need help finding P ( A ∩ B ): Suppose P(A)=P(A)=0.25 and P(B)=P(B)=0.62...
in
Probability / Statistics
@tkhunny: P(A \cap B) means the same thing as P(A\,\mathtt{AND}\,B), and in general it is given by: \displaystyle P(A \cap B) = P(A|B)P(B) =...
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6 replies | 326 view(s)
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