Need STATs help Please!!!

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rozayAce

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Mar 8, 2013
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Given the independant variable with mean =ux=120 and uy=300 The St. Dev is Qx= 12, Qy=16. What is the mean and ST.D of each veriibles
a) 0.8y+20 b)2x-100 c)x+2y

im not sure how to do this one at all with the formulas so please explain clearly. Please explain how you did this and show steps so that i can understand how it was done!!

#2. Lets say 13% of ppl are lift handed, if we randomly test 5 persons, find the probability of these:
a) some lefties among 5 ppl
b) there are exaclty three left handed ppl in the team
c) there are at least three lefted hands in the team
d)there are less than 3 lefties in the team

Again please explain how you did this thanks!
 
rozayAce said:
Given the independant variable with mean =ux=120 and uy=300 The St. Dev is Qx= 12, Qy=16. What is the mean and ST.D of each veriibles
a) 0.8y+20 b)2x-100 c)x+2y

im not sure how to do this one at all with the formulas so please explain clearly. Please explain how you did this and show steps so that i can understand how it was done!!

#2. Lets say 13% of ppl are lift handed, if we randomly test 5 persons, find the probability of these:
a) some lefties among 5 ppl
b) there are exaclty three left handed ppl in the team
c) there are at least three lefted hands in the team
d)there are less than 3 lefties in the team

Again please explain how you did this thanks!
Click to expand...

This is not a class-room. We try to help you with specific problem with specific "sticking-point".


You need to read the rules of this forum. Please read the post titled "Read before Posting" at the following URL:

http://www.freemathhelp.com/forum/th...217#post322217

We can help - we only help after you have shown your work - or ask a specific question (not a statement like "Don't know any of these")

Please share your work with us indicating exactly where you are stuck - so that we may know where to begin to help you.
 
rozayAce said:
Given the independant variable with mean =ux=120 and uy=300 The St. Dev is Qx= 12, Qy=16. What is the mean and ST.D of each veriibles
a) 0.8y+20 b)2x-100 c)x+2y

im not sure how to do this one at all with the formulas so please explain clearly. Please explain how you did this and show steps so that i can understand how it was done!!

#2. Lets say 13% of ppl are lift handed, if we randomly test 5 persons, find the probability of these:
a) some lefties among 5 ppl
b) there are exaclty three left handed ppl in the team
c) there are at least three lefted hands in the team
d)there are less than 3 lefties in the team

Again please explain how you did this thanks!
Click to expand...
What have you tried? Without seeing your work, we don't know where you are stuck, or what rules you know.

The first thing you should "know" is that whenever you add or subtract independent measurements, then Variances add.
Second thing is that if you multiply any distribution times a constant, that changes the scale of the entire distribution linearly, but if you add/subtract a constant, you only shift the mean.

#2 - are you supposed to use the Binomial Distribution, or work it out from scratch?
 
i dont know how to do the first one using binomial method. Im asking for you to solve the question with showing your work so i can understand how quetions like this are done. For the second one im not sure how to get the answers





DrPhil said:
What have you tried? Without seeing your work, we don't know where you are stuck, or what rules you know.

The first thing you should "know" is that whenever you add or subtract independent measurements, then Variances add.
Second thing is that if you multiply any distribution times a constant, that changes the scale of the entire distribution linearly, but if you add/subtract a constant, you only shift the mean.

#2 - are you supposed to use the Binomial Distribution, or work it out from scratch?
Click to expand...
 
Can you tell us -

what equation you would use to find the average of a set of numbers? Can you give us an example with say 10 numbers?

what equation you would use to find the standard deviation of a set of numbers? Can you give us an example with say 10 numbers?
 
rozayAce said:
Given the independant variable with mean =ux=120 and uy=300 The St. Dev is Qx= 12, Qy=16. What is the mean and ST.D of each veriibles
a) 0.8y+20 b)2x-100 c)x+2y
Click to expand...
If y = (300 ± 16), then what is 0.8*y? What is 20 + that number?

If x = (120 ± 12), what is 2*x? What is 100 less than that number?

For part c), you have to know how to add Variances. Can you find that rule in your text or notes?

#2. Lets say 13% of ppl are lift handed, if we randomly test 5 persons, find the probability of these:
a) some lefties among 5 ppl
b) there are exaclty three left handed ppl in the team
c) there are at least three lefted hands in the team
d)there are less than 3 lefties in the team
Click to expand...
Do you know the Binomial Distribution?
 
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