Calculating Probability - "At Least One" statements

[DarklightALBANIA]

Thanks god i don't live in San Francisco.....I live in Japan

[bp56789]

EARTHCAKES. Sounds tasty.

[dasilvd003]

Thank you so much



[frostyKB]

i think the last 2 problems are wrong

Isn't the probability of occurring 1 earthquake in 50 years is

0.02 + 0.98^49? 0.02 is probability of 1 earthquake during some random year,49probability of not happening

If it's 0.98^50 then you are calculating the possibility of no earthq occurring in 50 years

Or maybe i'm horribly wrong and confused

[Hower98]

@frostyKB Yeah, what you said was wrong, as 0.98 is the probability of not happening at a given year, 0,98^50 not happening in 50 years, you are right there, but 1 - P(not happening) is it happening at least once, which is what he was calculating. 0.2 + 0.98^49 would calculate the probability of one, not at least one.

[KylaiaJmaa]

Help me please. How would I find the answer to the question "If you flip a coin 3 times, what is the probability of getting heads at least 2 times?"

[Hower98]

@KylaiaJmaa You need to know Binomial probability I think... if you don't know what I'm talking about, best write out all the possible answers and add up all the ones with 2 or 3 heads, and calculate that way. Should be esay considering small numbers.

[KylaiaJmaa]

Oh my god THANK YOU! I've been trying to figure this out for the past 1/2 hour!

[Homer8j]

Why can't my actual statistics professor be this clear? Thank you for the help!

[Vaettir77]

you're automatically cool for being left handed

[Abu7929]

Nice video, I have a question though. What is the probability of learning to write with your right hand so you don't obscure half the board while you are writing ? :D

[meben7]

well at least i don't have to watch a your teacher.com vedio for this they drive me crazy

[patrickJMT]

@meben7 lol, why do they drive you crazy?

[lexinaut]

Very nicely presented (even though I live (yikes) in the bay area). As a teacher, I do try to raise awareness, since precautions such as SECURING TALL FURNITURE PROPERLY TO WALLS might be vital to one's survival if one gets hit by a whopperquake. It's not that expensive to do (although a stud finder might be needed to find wood to attach to). I DO QUAKE about QUAKES occasionally. It's a real danger. The entire Pacific Ocean sits in one great unstable RING OF FIRE. Disturbing, but true!

[bbdragon99]

Thank you so much

[sox5d]

you're better than my teacher

[annarose30]

hopefuly u used dice than earthquakes :-)

[Fashionpopsicle]

Most interesting math video ive ever seen!

[teranenrique]

Patrick you the man! Got math for IT students test and your videos just saved my skin! Thank you sir! You make a hell of a math professor!

[alfatourist]

I think the probability determination is only vaulabe when you compare it with other cities, and that gives you the whole range from safest to riskiest.

[KAYaKHA]

what about at least 3 E. in next 25 years?

[Cryptically]

4 letters and envelopes are addressed to 4 different people. If the letters are randomly inserted into the envelopes, what is the probability that at least one will be inserted in the correct envelope?

=5/8

how do you get to that??

[birthdaythesuit00]

I'm lost. I did the classic 'at least 1 girl in 4 children' set up and got

1-(.5)^4

is that right? so a 93.75% chance to have at least 1 girl in 4 kids?

i'm taking this online with no teacher available.../wrists

[moreepisode]

Thanks. i understood. it would be nice if you used marbles or cards as your examples.

[shutupsuckling]

Thanks. You probably should have used a much easier scenario. Balls in a bag of different colours or something. But I got the main point and worked my problem out. Cheers.

[xxchillenpinoyxx]

is there a video for probability with an "or" statement

[duyanh0701]

P(A or B)= P(A) + p(B) - P(A and B)

P(A AND B) is the probability that both of them happen

[itsthejeff2001]

i'm trying to figure out a very similar problem. so i don't have to explain my problem specifically, i'm going to use cards for an example.

i need to find the P(drawing at least 1 diamond) in two draws without replacing the first card. can you help?

[SinfulMentos]

You sound like Ned Flanders, sorta :DDD

[lombaxsecret]

hey! u uploaded this video on my birthday last year :D ... but neways, im doing leaving cert ordinary maths so these videos are helping me with homework! sound!

[yuukigahoshi]

at least now I know where I SHOULDNT live. haha

[pharoe14]

Let me guess, you don't live in San Francisco, do you? But in any case, fantastic videos. I'm taking intro into stats, and I "understand" everything, but this really gives me an upper hand because neither our book nor our professor really explains things in easy to understand terms.

[TheVinodvishwanath]

Thanks a million...as someone else said, lifesaver!

[trose77]

wow thanks so much! u are a life saver. made it so simple to understand

[Yay248]

thanks for the video, i totally get it now :)

[alfatourist]

By the book method it is .9+(.1*.9)=.99, the book method does not make sense to me. Can you explain the logic behind the book method? Please let me know if you need the actual question to explain the logic behind the book method.

[alfatourist]

Thanks PatrickJMT

I was confused about a question on finding the probability that at least one of the vendors deliver on time. I used your logic and understood the answer. The probability of the 1st seller will deliver is .9 and it is same for the 2nd seller. However, the 2nd seller delivering on time is only of consequence if the 1st seller fails to deliver on time, or .1. By your logic the calculation is (1-.1*.1=.99).

[tayy930]

THANK YOU!

[IshZ]

Thanks for the help

[omizi]

thanks man this helped

[MusicHero24]

im glad i dont live in san francisco!

[patrickJMT]

hahha, it is going to break off and fall in the ocean one day

[epicswell]

Ive a computer science exam later today and I just know that the "at least one" scenario will be up. Thanks for this. It helped a lot.

[patrickJMT]

good luck on the exam!!

[epicswell]

Just got the result - 98. Thanks for all the help with the vids ;-)

[patrickJMT]

very nice!! good job!!!! i remember how nice that always felt... : )

[kalakhatara]

THANK YOU SIR

[patrickJMT]

no problem!

[Feno900]

Maths confuses me so much at times but at times it just becomes very easy,this is one of those times where its just like. "Hey! This isnt all that hard." Ure rly good at explaining xD

[patrickJMT]

thanks! probability is one of those things that it seems like either you get it, or you dont at all! it is certainly very confusing at times. usually the problem is that people think that simple reasoning should determine a solution, but often, problems are very very complicated in nature!

[patrickJMT]

ya! fo sho!

[Waranle]

Thank you alot