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aussy123
Matching probability question help! Medal Rewarded!!
In a group of 100 persons, 85 had Rh positive blood (Rh factor present), 45 had Type O blood, and 38 had both type O and Rh positive blood. If one person had been selected at random from the group, what would the probability be: 1. that his blood type was Type O and Rh+? A. 3 /20 2. that his blood type was not O? B. 17/20 3. that his blood type was Rh-? C . 93/100 4. that his blood type was Type O and Rh-? D. 11/20 5. that his blood type was Rh+? E. 7/100 6. that his blood type was not Type O or else was Rh+? F. 19/50
a venn might be usefull
its a diagraham that defines sets with circles
Oh where can I find it
|dw:1366391420781:dw|
|dw:1366391462898:dw|
if we add the 3 sections we get: 85+45-38 = 92 so there must be 8 people in the setup that had neither Rh or O
|dw:1366391683621:dw|
this helps us define the numbers involved and the combinations that they ask for
1. that his blood type was Type O and Rh+? A. 38 /100 2. that his blood type was not O? B. (100 - 45)/100 3. that his blood type was Rh-? (not RH) C. (100 - 85)/100 4. that his blood type was Type O and notRh? D. 45/100 * C 5. that his blood type was Rh+? E. 85/100 6. that his blood type was not Type O or else was Rh+? F. B + E
One question just so I know Im reading the diagram right. Is Rh. n. O , Rh.NOT.O?
there are 2 symbols in set theory; "n" and "u" n = AND u = OR
ohh I see, makes sense.
"and" defines the intersection (commonality) of sets
im thinking F might be off
so #1 from what I see is A #2 is D
|dw:1366392293192:dw| notO or Rh is: (100-7)/100 i had a repetition in there
Ok now Im a bit confused.
notO includes the areas: 47, 8 Rh includes the areas: 47, 38 if we add these together to find the probability of notO or Rh, im doubling an area.
4. that his blood type was Type O and notRh? this one might be off as well |dw:1366392674723:dw| the commonality of O "and" notRH is spose to be 7/100
other than that, i think its sound :)
so was I right about #1 and #2
yes, it might help to rewrite the options in 100 format A. 15/100 B. 85/100 C . 93/100 D. 55/100 E. 7/100 F. 38/100 that should be more intuitive
@aussy123, @amistre64 has been quicker than me. I was preparing these tables for you. In the first table you have the given data in green and the calculated data in yellow. The other sisx tables correspond to each question of the problem where I have shaded in green the data to consider. Though late, I hope it helps
Oh Cool thats very helpful! Thanks to the both of you!!
nice tables, im not sure if i could process those in that manner ...
@amistre64, thanks. They are known as contingency tables in Statistics