Qualification > Math
statistics CIE AS level doubts!!
Tohru Kyo Sohma:
ok....i actually didnt know where to post my statistics doubts.......so i opened a new topic for it(dont ban me if i did a mistake).....so i had doubts in;
1. may/june 2007 qns1
2.oct/nov 2005 qns 1 and 6 part 2
3.may/june 2006 qns 1 and 2 part1 and 5 part4 and 6 part4
4.may/june 2005 qns 5 part3 and 6 part2 and 2 part1
5.oct/nov 2004 qns6
6.may/june 2004 qns 6 part3 and 7 part2
....ok....i guess that is alot to ask....and i'd be glad if u help me in some atleast!!!
Tohru Kyo Sohma:
ok...i got qns 1 answer!!
Ghost Of Highbury:
1. https://studentforums.biz/math-146/s1-doubts-here!!!!/msg413139/#msg413139
2. best to go with 2 pie-charts
males : Young = 40/100 360 = 144o
Middle 35/100 * 360 = 126o
Elderly 25/100 * 360 = 90o
Do the same for the females
. 6ii) Profit = 0, means he hits on the fourth throw or the fifth throw
4th = doesn't hit for the first three + hits in the 4th = (4/5)^3 * 1/5 = 0.1024
or 5th = doesn't hit for the first 4 + hits in the 5th = (4/5)^4 *1/5 = 0.08192
total = 0.184
3. q1)The data is skewed as there is an outlier = 352 (way above the rest)
Thus, go for median, arrange them in ascending order, and spot the middle one = 47 = 47000
q2 ii ) burgers for suppers = 0.5
meaning burgers after swimming, or not.
0.2*0.75 + 0.8*x = 0.5
x = 0.4375 ~ 0.438
5iv) 24 were b/w 25-30, 88 were>30
(24/110)(88/110) = 0.273
6iv) use ur answer to iii to determine mean and variance
mean = (1*16 + 2*8 + 3*4 + 4*2 + 5*2) / 32 ~ 1.94
variance = sum (xi^2/total f) - 1.94^2 = 166/32 - 1.94^2 ~ 1.43
4. 5iii) Independent if P(A) * P(B) = p(A and B)
ain't the case here, so not independent.
6ii) P(1.9-b<X<1.9 +b) = P(1.9-b-1.9 / 0.15 < Z < 1.9+b-1.9 / 0.15) = 80% = 0.8
P(-b/0.15 < Z < b/0.15) = 0.8
@(b/0.15) - (1-@(b/0.15) = 0.8
2@(b/0.15) -1 = 0.8
@(b/0.15) = 0.9
b/0.15 = 1.282
b = 0.1923
thus the limits are 1.9-b = 1.71 and 1.9+b = 2.09
2i) sqrt(sum(xi^2fi)/26 - mean^2 = (5^2*2 + 15^2 *9 + ....)/26 - 27.5^2) = 16.1
gotta sleep now, will do the rest 2morrow
Tohru Kyo Sohma:
--- Quote from: Ghost Of Highbury~ on May 19, 2011, 07:05:58 pm ---1. https://studentforums.biz/math-146/s1-doubts-here!!!!/msg413139/#msg413139
2. best to go with 2 pie-charts
males : Young = 40/100 360 = 144o
Middle 35/100 * 360 = 126o
Elderly 25/100 * 360 = 90o
Do the same for the females
. 6ii) Profit = 0, means he hits on the fourth throw or the fifth throw
4th = doesn't hit for the first three + hits in the 4th = (4/5)^3 * 1/5 = 0.1024
or 5th = doesn't hit for the first 4 + hits in the 5th = (4/5)^4 *1/5 = 0.08192
total = 0.184
3. q1)The data is skewed as there is an outlier = 352 (way above the rest)
Thus, go for median, arrange them in ascending order, and spot the middle one = 47 = 47000
q2 ii ) burgers for suppers = 0.5
meaning burgers after swimming, or not.
0.2*0.75 + 0.8*x = 0.5
x = 0.4375 ~ 0.438
5iv) 24 were b/w 25-30, 88 were>30
(24/110)(88/110) = 0.273
6iv) use ur answer to iii to determine mean and variance
mean = (1*16 + 2*8 + 3*4 + 4*2 + 5*2) / 32 ~ 1.94
variance = sum (xi^2/total f) - 1.94^2 = 166/32 - 1.94^2 ~ 1.43
4. 5iii) Independent if P(A) * P(B) = p(A and B)
ain't the case here, so not independent.
6ii) P(1.9-b<X<1.9 +b) = P(1.9-b-1.9 / 0.15 < Z < 1.9+b-1.9 / 0.15) = 80% = 0.8
P(-b/0.15 < Z < b/0.15) = 0.8
@(b/0.15) - (1-@(b/0.15) = 0.8
2@(b/0.15) -1 = 0.8
@(b/0.15) = 0.9
b/0.15 = 1.282
b = 0.1923
thus the limits are 1.9-b = 1.71 and 1.9+b = 2.09
2i) sqrt(sum(xi^2fi)/26 - mean^2 = (5^2*2 + 15^2 *9 + ....)/26 - 27.5^2) = 16.1
gotta sleep now, will do the rest 2morrow
--- End quote ---
hehe....thanks alot anyways....sleep tight...dont let the bed bugs bite ;D
Tohru Kyo Sohma:
ok...i have 1 more doubt....may/june 2007 qns 3 (b)
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