Question

4.Compare P (AnB) with P (A U B), and explain what each probability means in the context of the situation and data you collected.
Table: boys girls
homework 58 62 120
no homework 23 22 45
81 84 165

Answer 1

@amistre64

Answer 2

define event A and event B

Answer 3

A=No homework and B=Girls

Answer 4

Are A and B independant or dependant?

Answer 5

this is what i did for question 3.
P(A l B) = 22/84 ≈0.26=26%
26% of no homework represent the girls.
P(A l B)=22/45=0.04= 4%
4% of the no homework is girls.
No we can see that P (A l B) ≠ P (B l A).

Answer 6

P(homework | girls) is not 22 out of 84, its 62 out of 84

Answer 7

P(homework|all events) = 120 out of 165

Answer 8

i was doing the no homework number

Answer 9

*numbers

Answer 10

... these old eyes of mine lol

Answer 11

lol, its okay :)

Answer 12

fine ...

P(no hw | girls) = 22/84
P(no hw | all events) = 45/165

since the P(no hw) changes depending on the given condition; P(no hw) is not independant

Answer 13

For question 3 the second answer equation is B l A not A l B

Answer 14

oaky so it would be 3%?

Answer 15

\[P(A|B)=\frac{P(AnB)}{P(B)}\]
\[P(A|B)~P(B)={P(AnB)}\]
if P(A) is independant of a given condition, then P(A|B) = P(A)
\[P(A)~P(B)={P(AnB)}~\text{, if}~P(A|B)=P(A)\]

Answer 16

could u show me with the numbers in place?

Answer 17

P(AuB) = P(A) + P(B) - P(AnB)

so the determing the independant nature if useful in some aspects

P(AuB) = P(A) + P(B) - P(A|B) P(B)

Answer 18

P(no hw | girls) = 22/84

P(no hw | all events) = 45/165

the P(no hw) is not independant

P(no hw and girls) = 22 out of 165

or stated another way

P(no hw and girls) = P(no hw| girl) * P(girls)
= 22/84 * 85/165

Answer 19

84/165 that is

Answer 20

im so sorry, open study is acting up...

Answer 21

or maybe its just my computer

Answer 22

so it would come out as 4%

Answer 23

P(AnB) = 22/165 = .1333, or 13.33%

Answer 24

yea. i was just finna write that. didnt do the whole problem

Answer 25

P(AuB) = (84+45-22)/165

Answer 26

its 65%

Answer 27

u there?

Answer 28

lets make sure i understand what your question is to start with.

can you post it?

Answer 29

sure.

Answer 30

Pose a question for which a two-way table is appropriate.
Boys Girls Total
Homework 58 62 120
No homework 23 22 45
Total 81 84 165



3. Choose a row and column and compare P (A | B) with P (B | A). Explain what each probability means in the context of the situation and data you collected.
Let A=No homework and B=Girls
P(A l B) = 22/84 ≈0.26=26%
26% of no homework represent the girls.
P(B l A)=22/165=0.27= 3%
3% of the no homework is girls.
No we can see that P (A l B) ≠ P (B l A).
4. Compare P (A∩B) with P (A∪B), and explain what each probability means in the context of the situation and data you collected.

Answer 31

P(B|A) is not right, 22 girls out of 45 no hw, 22/45

Answer 32

0.48888888888=5%

Answer 33

no, you are confusing probability with percentage. move 2 decimal places

Answer 34

.4888 -> 48.88%

Answer 35

ooo,im really horrible at math.... sorry

Answer 36

i seem to have worked out 4 in my previous postings :)

Answer 37

wow!!! u did.... im sorry for wasting ur time!!!!!! thanks for all ur help though, and putting up with me :) @amistre64

Answer 38

'sok, good luck :)