Against All Odds
Our favorite Geneticist
Pardi Sabeti
P(rain) stands for what?
The probability of rain.
I want to know how Earthlings feel about Space Travel. Should I attempt to ask EVERY Earthling or should I use a different tool? What is the tool?
You should take a sample of all Earthlings. GROK!
If you get struck by lightening once, are you more likely to get struck by lightening again?
No! These are separate events and they don't influence one another.
If the P(Raining on Monday) is 95% what is the P(Not Raining on Monday)?
5% because either it will rain or not and that is all the possible outcomes.
I need to find out how many mothers in the school have computers at home. I ask my friends to ask their moms because I figure that is a good sample. Did I do anything wrong in collecting my data this way?
Yes, that would be a biased sample because your friends aren't typical of the whole community.
If you lose the lottery five times in a row, are you more likely to win the next time?
No! These are separate events and don't influence one another.
If P(sunshine)=.65 and P(traffic accident on I5 during the morning commute)=.23, what is the P(sunshine AND a traffic accident)?
P(sunshine) times P(traffic accident)=.65 times .23=.1495 or about 15%.
How did the company know which potato chips were sample chips? How did they mark them?
They punched a hole in the potato before slicing and the samples all had a hole in the middle!
Why is the lottery called "the game for the statistically impaired"?
Because it is you are so unlikely to win, it is almost a zero probability.
You have a STANDARD deck of cards. What is P(drawing a King)? What is P(drawing a heart)?
P(drawing a King) is 4/52 and P (drawing a heart) is 13/52
If I want to survey typical classrooms at Roosevelt for political attitudes, how do pick the classrooms?
Randomly! Put room numbers in a hat and draw out five or so.
In the tall persons club, did the men and women have to have an equal z-score in order to join?
No, women had to have a HIGHER z-score to get in. HMMMM!
What is the P(drawing a KING OR drawing a HEART) from a STANDARD deck of cards?
P(King) + P(Heart) minus the P(King of Hearts) because otherwise we would count it twice. So 4/52 +13/52 - 1/52= 16/52
The teachers on the third floor never want to do the annual school survey with their students because they are busy teaching, so they don't participate. Does it matter in terms of the data? Give an example.
Yes! There are a lot of math teachers on the third floor so the students who take math classes wouldn't be a part of the survey. That would make the data biased.