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Mathematics: Post your doubts here!

parthrocks

parthrocks

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An unbiased dice is thrown once. Write down the probability distribution of the score X and show that Var(X) = 35/12 = I've done this!!!

The same dice is thrown 70 times.
a) Find the probability that the mean score is less than 3.3.
here my doubt is only when i take the continuity correction into consideration i get the answer which tallies bt when i dont as my miss told because here the data is not converted from binomial to normal so we dont have to taken then bt when i treied what my miss told even then i didnt get!!!where am I wRONG????reply soon frined
the b part says)
b) Find the probability that the total score exceeds 260.
is this somewhat related to the first part explain!!!
the answers:-
a part)0.155
b part)0.845
reply soon at whitecorp
 
Taiyaba

Taiyaba

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Find the length of the line segment : (p,q) and (q,p)
Guys I knw ths one is v simple bt if anyone can tell me hw to do it bcx I thnk I m doing something wrong
 
aloha

aloha

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can anyone tell me how to solve these 2 following questions:
1)there is a population of bacteria 500000 at start....it increases 10 % every hour...how long will it to reach 4 million?
2) a car cost 29000. anne puts 400 dollars in her account which is compounded monthly at 0.1%....how long will this take for her to buy the car??/
 
Bilal Khan

Bilal Khan

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aloha said:
can anyone tell me how to solve these 2 following questions:
1)there is a population of bacteria 500000 at start....it increases 10 % every hour...how long will it to reach 4 million?
2) a car cost 29000. anne puts 400 dollars in her account which is compounded monthly at 0.1%....how long will this take for her to buy the car??/
Click to expand...
1) it will take 70 hrs.
 
Scafalon40

Scafalon40

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Hi all, I was wondering if someone could solve this:
Divide 2x^4 - 5x^3 - 16x^2 - 6x by 2x^2 + 3x
 
snowbrood

snowbrood

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The sides of a parallelogram lie along the lines y = 2x - 4, y = 2x - 13 , x + y = 5 and x + y = -4. Find the length of one side, and the perpendicular distance between this and the parallel side. Hence find the area of the parallelogram. can anyone help
 
snowbrood

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the sides of a parallelogram lie along the lines y=2x-4 ,y=2x-13,x+y=5 and x+y=-4 find the length of one side and the perpendicular distance between this and the parallel side hence find the area of the parallelogram can anyone tell me how to find the perpendicular side??
 
whitecorp

whitecorp

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leadingguy said:
sorry bt i did not get it..... :(
how is b/0.15 = 1.28 and


1.28 is invewrse of what???? explain in detail as clear as u can ... I will be thankful to u .. mate .
Click to expand...

Let's just look at the left shaded area of the normal distribution curve which I previously have drawn. We assume the dotted line has a value of -a. Then we seek to find a through the following: P(Z<-a) = 0.1 =====> -a= invNorm (0.1) = -1.282 .

If we examine the problem carefully, we realize that in fact we are merely further saying that P( -a<Z<a) =0.8 , which therefore gives rise to the fact that a =b/1.5 =1.282.

Hope this helps. Peace.
 
N.M

N.M

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Q.Find the stationary points of the graphs of
y=2x^2 + e^-x^4
And determine the nature of the curve(s)
 
parthrocks

parthrocks

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can u plz help me plz its from my statistics 2 textbook for a levels
chapter:-estimation
Unbiased estimates of the mean and variance of a population, based on a random sample of 24 observations, are 5.5 and 2.42 respectively. Another random observation of 8.0 is obtained. Find new unbiased estimates of the mean and variance with this new information.
Assuming that the sample mean has a normal distribution,estimate the probability,estimate the probability that a sample mean based on a sample size of 25 is within 0.01 of the population mean,,,,,,,Explain why your answer is only an estimate!!!help fast need it urgenty sir!
whitecorp
 
whitecorp

whitecorp

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N.M said:
Q.Find the stationary points of the graphs of
y=2x^2 + e^-x^4
And determine the nature of the curve(s)
Click to expand...

You would have to differentiate both sides wrt x,
ie dy/dx = 4x + (-4x^3)* (e^-x^4) and set dy/dx=0.
To obtain the roots of this equation, you will have to use your graphic calculator.
Subsequently, you can either use the second order derivative or the sign test method to ascertain the nature of the stationary values.

Hope this helps. Peace.
 
whitecorp

whitecorp

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snowbrood said:
the sides of a parallelogram lie along the lines y=2x-4 ,y=2x-13,x+y=5 and x+y=-4 find the length of one side and the perpendicular distance between this and the parallel side hence find the area of the parallelogram can anyone tell me how to find the perpendicular side??
Click to expand...

Recognize that one pair of parallel sides lie along y=2x-4 and y=2x-13 (they have the same gradient value of 2), while the other pair lie along x+y=5 and x+y =-4 (they have the same gradient value of -1) . Graph out these 4 lines and convince yourself the above fact is correct.

Next, based on the graph you have drawn, you will be able to identify two points which will form one side of the parallelogram. Solve for the full coordinates of these two points through the simultaneous intersection of specific lines and hence determine the length of this side.

From the diagram, see if you can also draw an imaginary line from one of the above two points and extend it such that it is perpendicular to the opposite side of the parallelogram. This is the perpendicular side which the question is talking about.

Hope this helps. Peace.
 
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