ShmoopTube
Where Monty Python meets your 10th grade teacher.
Search Thousands of Shmoop Videos
Statistics, Data, and Probability I Videos 30 videos
Statistics, Data, and Probability I: Drill Set 1, Problem 1. What is the mean yearly salary?
Statistics, Data, and Probability I: Drill Set 1, Problem 2. What is the median length of these writing utensils?
CAHSEE Math Statistics, Data, and Probability I: Drill Set 1, Problem 3. The mode of the number of days in each month for a single non-leap year is...
CAHSEE Math 5.2 Statistics, Data, and Probability I 193 Views
Share It!
Description:
Statistics, Data, and Probability I: Drill Set 5, Problem 2. What is the probability she will pull out a 20, and likely be the creature's first victim?
Transcript
- 00:03
Here's a shmoopy problem for you...
- 00:05
Mrs. Dolthauser insists on every activity being fairly organized...
- 00:10
...even a student evacuation when the school is under attack by a mutant sea creature.
- 00:15
Dolthauser's 20 students are randomly drawing numbers out of a bag to determine
- 00:19
the order in which they are able to get the heck out of there.
Full Transcript
- 00:22
Each student gets to keep the numbered piece of paper that he or she draws out of the bag.
- 00:26
Jose picks first and draws a 10, so he will go tenth, behind nine other students.
- 00:32
Jenna picks next.
- 00:33
What is the probability that she will pull out a 20...
- 00:36
and likely be the creature's first victim?
- 00:38
And here are the potential answers...
- 00:42
OK, so what is this question really asking?
- 00:45
Well, it's a slightly more complicated probability question with a twist.
- 00:49
That is, if it only asked for the odds of pulling one number out of 20 random numbers,
- 00:54
that'd be pretty straightforward right, but Jose has gone and made things more complicated for us.
- 01:00
Why? Because he stuck his number in his pocket.
- 01:02
Because in this case, one number is now being removed -- so the total is no longer 20 -- it's 19.
- 01:10
So Jenna is drawing for a card labeled "20" out of only 19 possible choices.
- 01:16
So her odds are now... one in 19.
- 01:20
With the 10th card removed from the deck,
- 01:22
her odds of drawing the 20th number just went UP.
- 01:26
The answer is B.
- 01:28
Sadly, Jenna does indeed pick the 20.
- 01:31
Fortunately for her though, the sea creature likes its meat... well done.
Related Videos
SAT Math: Statistics and Probability Drill 1, Problem 2. If the four largest numbers in the set were doubled, what would happen to the median...
SAT Math 1.4 Statistics and Probability. If two standard 6-sided dice are rolled, what is the probability that the sum of the dice will be gre...
SAT Math 1.5 Statistics and Probability. If Silas draws one card, then places it in his pocket and draws another, what is the probability that...
CAHSEE Math: Algebra and Functions Drill 5, Problem 3. Solve the equation.