## anonymous 3 years ago I need to know if I use the Poisson Distribution for problem 5 (A-C).

1. anonymous

2. anonymous

No use the Binomial distribution p= 1/3 for tie p=1/6 for "0-0" tie

3. anonymous

so i would use this formula: P^k * (1-p)^n-k and for part A, I would plug in 10 for n and 3 for k???

4. anonymous

@jim_thompson5910 @karatechopper @JuanitaM

5. anonymous
6. anonymous

n=10 and k=3

7. anonymous

so im correct. woohoo! :D

8. anonymous

haha :)

9. anonymous

ok, so i get .0021676912. is that the final answer or is there anything else i needa do?

10. anonymous

for part A ? i get about 0.26

11. anonymous

yeah, how'd u get .26 ??

12. anonymous

just plugged numbers in formula ... well i cheated and used Excel :) p = 1/3 n=10 k=3 $\rightarrow \left(\begin{matrix}10 \\ 3\end{matrix}\right)*(\frac{1}{3})^{3} *(\frac{2}{3})^{7} = 120*\frac{128}{3^{10}} = 0.2601$

13. anonymous

im confused about the second half... after the first equal sign

14. anonymous

$\left(\begin{matrix}10 \\ 3\end{matrix}\right) = \frac{10!}{7! 3!} = 120$ $(\frac{1}{3})^{3} *(\frac{2}{3})^{7} = \frac{1}{3^{3}}*\frac{2^{7}}{3^{7}} = \frac{2^{7}}{3^{10}} = \frac{128}{59,049}$

15. anonymous

ok. so i was getting .0021676912 because i didn't multiply it by 120. makes sense.

16. anonymous

so for part B i would just change p to 1/6 ??? (why 1/6 again?) and for part C i would do 1-part B ???

17. anonymous

its 1/6 because its half of 1/3 --> 1/3 * 1/2 = 1/6 part C is looking at chance you tie but Not 0-0 --> 1/3 - 1/6 = 1/6

18. anonymous

o because half would equal zero-zero ??

19. anonymous

right

20. anonymous

and part Cs answer will basically be the same as part B since they're both p=1/6?

21. anonymous

umm yep thats what it looks like

22. anonymous

ok coo ! :)

23. anonymous

alright, so im on #7 and it's wanting the same info as #6 but normally distributed... would i use : f(x)= ( 1 / [sigma * sqrt(2pi)] ) * e ^ (x-mu/sigma) to plug in the same info from 6???

24. anonymous

here are the answers to #6: a) picture b) 1/(b-a) = 1/(210-150) = 1/60 c) (160-150)/(210-150) = 10/60 = 1/6 d) 1/6 * 1/6 = 1/36 e) (185-165)/(210-150) = 20/60 = 2/6 f) (210-200)/(210-150) = 10/60 = 1/6

25. anonymous

|dw:1360115375877:dw|

26. anonymous

yes that is the function for normal distribution but since its complex....you need to use probability table for normal distribution problems you have to determine z-score (standardized value) first anyway, check your answers from #6 again first though the mean has to be a number between 150 and 210 .... not 1/60

27. anonymous

i got 1/60 by using the formula but i guess thats not correct since it makes no sense to have a mean of 1/60. i guess the mean is 180 ( 150+210 / 2 )

28. anonymous

@satellite73 can you continue where @dumbcow left off??? they are no longer online. :(

29. anonymous

4 is poisson, 5 is binomial

30. anonymous

what number are you on?

31. anonymous

number 7

32. anonymous

it's asking me to repeat the steps of #6 but idk what to really do

33. anonymous

damn i don't know squat about the normal distribution sorry

34. anonymous

its like the picture i drew above ^^^

35. anonymous

i know, but you need a table to calculate these

36. anonymous

the mean is 180 right?

37. anonymous

yes and the standard deviation is 20

38. anonymous

then you need to convert to a z score or something right? so you can look these up in a table

39. anonymous

ok yeah

40. anonymous
41. anonymous

for example $\frac{165-180}{20}=-.75$

42. anonymous

and $\frac{185-180}{20}=.25$ so you need to use a table to find the area under the normal curve between $$-.75$$ and $$.25$$

43. anonymous

you can use this http://www.danielsoper.com/statcalc3/calc.aspx?id=2

44. anonymous

i dont think thats how it works... are both sides supposed to be equal but opposite?

45. anonymous

no

46. anonymous

*arent

47. anonymous

not unless they happen to be your question is between 165 and 185 which is not symmetric about 180 it is 5 up and 10 down

48. anonymous

so your job is to find the area under the curve from -.75 to .25 this takes a couple steps

49. anonymous

from the table , to the left of .25 is 0.59870633 and to the left of -.75 is 0.2266273 so you use $0.59870633-0.2266273$

50. anonymous

you got that?

51. anonymous

im soaking it all in

52. anonymous

the normal curve is symmetric the way the tables work is that they give you the area under the curve to the left of your z score so if you want the area between two z scores you take the larger z score, find the area in a table, then take the smaller area, and subtract

53. anonymous

|dw:1360121214382:dw|

54. anonymous

|dw:1360121361823:dw|

55. anonymous

area between -.75 and .25 is what you want it is the area to the left of .25 minus the area to the left of -.75

56. anonymous

yeah i see what you are doing

57. anonymous

ok good

58. anonymous

site is freezing up on me, but you can use the calculator i linked to find the z scores, then the area you want

59. anonymous

ok so we get 0.37207903 or 37% chance ?

60. anonymous

i am having trouble scrolling up, but i did find the numbers you need, i just didn't subtract

61. anonymous

yeah that looks right

62. anonymous

can you assist me with #8 too?

63. anonymous

|dw:1360121910130:dw|

64. anonymous

where do i go from here??

65. anonymous

we got to look in a table and see what the right hand point give 97.5 % of the area (so the left hand point will have 2.5% and the area between them will be 95%

66. anonymous

do you have a table?

67. anonymous

oh forget what i wrote above you just need to go to 95% short people can sit anyway

68. anonymous

im confused. can you reword.

69. anonymous

i think 95% of the people lie within two standard deviations of the mean, meaning if you look at the table you should see for .95 a z score of 2 you have to check this because i do not have a table if this is true, then two standard deviations is 40 and 180 + 40 = 120 is the max height

70. anonymous
71. anonymous

yeah we can use that

72. anonymous

.82894

73. anonymous

so we find .95 in the table, and see what the corresponding z score is

74. anonymous

looks like about 1.64 or 1.65 half way between them actually lets pick one

75. anonymous

for the sake of argument, lets say the z score is 1.64 then we convert back to height $1.64\times 20+180$ will give what we want

76. anonymous

remember we computed the z score for say $$x$$ by $\frac{x-180}{20}$ so if $\frac{x-180}{20}=1.64$ then $x=1.64\times 20+180$

77. anonymous

...ok

78. anonymous

and then what?

79. anonymous

thats the final answer??

80. anonymous

yeah i forgot what the question was can you repost so i don't have to keep scrolling down?

81. anonymous

82. anonymous

nvm the limit of the height adjustment is what you wanted so yes, that should be the answer

83. anonymous

should i solve or leave as is

84. anonymous

of course they want a number i would say about 213 or so

85. anonymous

the next one is similar find .98 in the body of the table, find the corresponding z score and work backwards to find the height

86. anonymous

i got 221 as my final answer

87. anonymous

looks like a z score of about 2.05 there is nothing really profound about this, it just says that 98% are less than 2.05 standard deviations above the mean since the standard deviation is 20 and the mean is 180 that means 98% are under $$2.05\times 20+180=221$$ cm tall

88. anonymous

for the 98 % curve

89. anonymous

yeah i go the same thing gotta run good luck!

90. anonymous

thanks a lot!