Probability

zee-f · 2011-08-26 08:28:50

checking if i did this correct

1. Flip a coin 5 times and record the outcomes here.

p(HEADS)=3/5

p(teals) = 2/5

bobbym · 2011-08-26 08:30:16

Hi;

What was the number of heads you counted?

zee-f · 2011-08-26 08:39:09

i got 3 heads and 2 teals

bobbym · 2011-08-26 08:41:03

Then your empirical probability is:

P(H) = 3 / 5
P(T) = 2 / 5

zee-f · 2011-08-26 09:17:21

so what i did was correct ?

bobbym · 2011-08-26 09:26:31

Yep, how about flipping it 10 times?

zee-f · 2011-08-26 09:29:05

if i flip it 10 times i put the ten in the denominator and how many times i got the heads or teals on the numerator if i add these i would get one

bobbym · 2011-08-26 09:35:53

True. But how about actually doing the experiment?

zee-f · 2011-08-27 01:53:07

ok so i flipped it i got p(t)=7/10 p(h)=3/10

zee-f · 2011-08-27 02:49:33

1. Flip a coin 5 times and record the outcomes here.

1- p(h)= (3/5)

p(t)= (2/5)

2. Start again. Flip the coin 25 times and keep track of the outcomes. Record them here.

2- p(h)=(15/25) p(t)=(10/25)

Draw a histogram from the data in question 1, and a separate histogram from the data in question 2. Also draw a histogram displaying the theoretical probability of head and tail outcomes. Use these to answer questions 3-5.

so i did draw a histogram for question one and two but i dont get this part of the question Also draw a histogram displaying the theoretical probability of head and tail outcomes

bobbym · 2011-08-27 04:14:55

Hi zee-f;

The theoretical probability of heads and tails is 12.5 / 25 each.

zee-f · 2011-08-27 04:49:20

how did u get that 12.5?

bobbym · 2011-08-27 04:50:40

Did your teacher go over any part of probabilty?

zee-f · 2011-08-27 09:44:27

yup this is what it said in the lesson

Probability is the chance that an event will occur. There are two types of probability: experimental and theoretical.

Experimental probability is probability based on collected data or information and it may be expressed mathematically in the following way (P(desired outcome) is read "the probability that the desired outcome will occur"):

what i dont get is this

Draw a histogram from the data in question 1, and a separate histogram from the data in question 2. Also draw a histogram displaying the theoretical probability of head and tail outcomes. Use these to answer questions 3-5.

ok so for the first one p(h)=3/5 and p(t)=2/5

i draw a histogram for that and

this p(h)=15/25

p(t) = 10/25

i draw a histogram for that to but what is Also draw a histogram displaying the theoretical probability of head and tail outcomes. helpppppp plzzzzzz

bobbym · 2011-08-27 09:47:58

Hold on! What did she say to you about theoretical probability?

zee-f · 2011-08-27 09:54:35

Probability is the chance that an event will occur. There are two types of probability: experimental and theoretical.

Experimental probability is probability based on collected data or information and it may be expressed mathematically in the following way (P(desired outcome) is read "the probability that the desired outcome will occur"):

this is what she said

zee-f · 2011-08-27 09:55:48

P(heads) = 1/2 and P(tails) = 1/2.

Notice again that P(heads) + P(tails) = 1. This will always be true for theoretical probabilities as well.

Another interesting thing about experimental and theoretical probabilities is that, the more trials you perform, the closer the experimental probability gets to the theoretical probability. So, the more times I flip that coin, the closer experimental probabilities will be to the theoretical probability of 1/2 for each outcome.

I could do an example with this, but it's really more convincing if you try it yourself. Just grab a coin and keep track of the outcomes for 10 flips. Then flip the coin 10 more times and combine all of the results. You'll see that the results for 20 flips come out closer to half heads and half tails than the results for 10 flips.

bobbym · 2011-08-27 09:59:26

Do you understand that?

zee-f · 2011-08-27 10:12:00

yup i get the experimental part but the theoretical probability is confusing

zee-f · 2011-08-27 10:18:11

1. Flip a coin 5 times and record the outcomes here.

p(h)=3/5

p(t)= 2/5

2. Start again. Flip the coin 25 times and keep track of the outcomes. Record them here.
p(h)=15/25

p(t)=10/25

3. Verify that the sum of the experimental probabilities of flipping heads or tails add up to 1. Check both sets of your data. Show your work.

They do add up to one for my first one 3/5+2/5=1

15/25+10/25=1

zee-f · 2011-08-27 10:20:00

these are confusing i dont even get the theoretical probability
4. Did you notice that your experimental data from question 2 was closer to the theoretical probability than your data from question 1? Explain briefly using your data to support your answer.

5. Predict the experimental probabilities of flipping heads or tails if you flipped the coin a total of 100 times. Use information from the lesson as well as your experimental data to support your answer.

bobbym · 2011-08-27 10:22:33

Hold it! You are not listening to me. You are running ahead to more questions.

We are trying to answer the question of do you understand a theoretical probability? If not, we start there.

zee-f · 2011-08-27 11:11:52

nope i dont understand the theoretical probability its confusing

bobbym · 2011-08-27 11:29:53

If the probability of throwing one head is 1 / 2 and the probability of throwing 1 tail is 1 / 2 and we throw a coin 10 times we expect 10 * ( 1 / 2 ) = 5 heads. And 10 * ( 1 / 2 ) = 5 tails on the average.

So if we throw a coin 25 times we expect 25 * ( 1 / 2 ) = 12.5 heads on the average.

zee-f · 2011-08-28 01:37:06

oooooooooh ok i get it now thank you soooooooo much so for the first one if i throw a coin 5 times i expect 5*(1/2)= 2.5

isnt the right for the first one ?

Math Is Fun Forum

#1 2011-08-26 08:28:50

Probability

#2 2011-08-26 08:30:16

Re: Probability

#3 2011-08-26 08:39:09

Re: Probability

#4 2011-08-26 08:41:03

Re: Probability

#5 2011-08-26 09:17:21

Re: Probability

#6 2011-08-26 09:26:31

Re: Probability

#7 2011-08-26 09:29:05

Re: Probability

#8 2011-08-26 09:35:53

Re: Probability

#9 2011-08-27 01:53:07

Re: Probability

#10 2011-08-27 02:49:33

Re: Probability

#11 2011-08-27 04:14:55

Re: Probability

#12 2011-08-27 04:49:20

Re: Probability

#13 2011-08-27 04:50:40

Re: Probability

#14 2011-08-27 09:44:27

Re: Probability

#15 2011-08-27 09:47:58

Re: Probability

#16 2011-08-27 09:54:35

Re: Probability

#17 2011-08-27 09:55:48

Re: Probability

#18 2011-08-27 09:59:26

Re: Probability

#19 2011-08-27 10:12:00

Re: Probability

#20 2011-08-27 10:18:11

Re: Probability

#21 2011-08-27 10:20:00

Re: Probability

#22 2011-08-27 10:22:33

Re: Probability

#23 2011-08-27 11:11:52

Re: Probability

#24 2011-08-27 11:29:53

Re: Probability

#25 2011-08-28 01:37:06

Re: Probability

Board footer