12.4.2
Section 12.4.2 Blog Entry:
Having read section 12.4.2 in the text:
Difficult:
It states on page 824 that it is important not to round to the nearest integer in some cases since it can lead you to draw incorrect and inaccurate conclusions. But, I was just wondering, how many decimal places should answers usually be rounded to?
After reading the paragraph description about the blue box rule for any random variable on page 826 which states "let a and b be constant. Then E(aX+b) = a(EX)+b and var(aX+b) =(a^2)var(X) I still cannot figure out exactly what this statement meants and how these two sides of the equation are equivalent.
On page 830, when the text discusses the idea of independence using the new notations for the random variables, do the notations for when X and Y are discrete random variables P(X=x,Y=y) = P(X=x)P(Y=y) imply an intersection between X and Y variables as it is written in the definition of independence?
Reflective:
In this section, I was a bit surprised at the terminology and vocabulary. I have encountered and applied the ideas of standard deviation, variance, averages, relative frequencies, etc, but I have never actually heard or used words like expected value (mean). I think knowing the different names or labels for certain values or concepts will be rather useful and a good thing to keep track of, since in other situations, either of the terms could appear. I have dealt with variance before, but the notations in this particular formula/definition were a bit new and foreign to me (page 825 Definition of variance).
Having read section 12.4.2 in the text:
Difficult:
It states on page 824 that it is important not to round to the nearest integer in some cases since it can lead you to draw incorrect and inaccurate conclusions. But, I was just wondering, how many decimal places should answers usually be rounded to?
After reading the paragraph description about the blue box rule for any random variable on page 826 which states "let a and b be constant. Then E(aX+b) = a(EX)+b and var(aX+b) =(a^2)var(X) I still cannot figure out exactly what this statement meants and how these two sides of the equation are equivalent.
On page 830, when the text discusses the idea of independence using the new notations for the random variables, do the notations for when X and Y are discrete random variables P(X=x,Y=y) = P(X=x)P(Y=y) imply an intersection between X and Y variables as it is written in the definition of independence?
Reflective:
In this section, I was a bit surprised at the terminology and vocabulary. I have encountered and applied the ideas of standard deviation, variance, averages, relative frequencies, etc, but I have never actually heard or used words like expected value (mean). I think knowing the different names or labels for certain values or concepts will be rather useful and a good thing to keep track of, since in other situations, either of the terms could appear. I have dealt with variance before, but the notations in this particular formula/definition were a bit new and foreign to me (page 825 Definition of variance).
posted by Jhan at
11:08 PM
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