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 6.5 Statistics, Data, and Probability I 189 Views
Share It!
Description:
Statistics, Data, and Probability I: Drill Set 6, Problem 5. What is the probability that the man will first pick a brown eyeball and then a white eyeball?
Transcript
- 00:03
Here's a shmoopy question for you...
- 00:05
There are six brown, four blue, four green,
- 00:08
and ten white eyeballs in an unmarked duffel bag recently found near the Jersey shore.
- 00:14
A well-dressed man with a loud tie, without looking,
- 00:17
must choose one at random and then pick a second eyeball.
Full Transcript
- 00:21
What is the probability that the man will first pick a brown eyeball, and then pick a white eyeball?
- 00:27
And here are our potential answers:
- 00:31
OK, so what is this question asking, anyway?
- 00:34
Other than... "what in the world is going on here?"
- 00:37
By the way... if the thought of touching eyeballs doesn't gross you out, you may want to consider
- 00:41
the field of optometry as a career choice -- it can be quite lucrative.
- 00:45
Anyway, what we have here is a two-step probability problem.
- 00:48
We are being tested in large part on whether we can recognize DEPENDENT and INDEPENDENT events.
- 00:54
In this case, we have to feel that red light flashing and recognize that these events are DEPENDENT...
- 01:00
...because after taking out the first eyeball... and not putting it back... our total will
- 01:05
diminish by one.
- 01:07
So the total eyeballs are: 6 plus 4 plus 4 plus 10... or 24.
- 01:14
There are 6 brown eyeballs, so the odds of first choosing a brown from the duffel bag
- 01:19
are 6 in 24... or 1 in 4 once that fraction gets... melted down...
- 01:25
We are now left with 23 eyeballs... and note that we only have 5 brown ones left.
- 01:31
So the well-dressed man picks again, hoping for a white eyeball...
- 01:34
...his odds are 10 in 23 here because there are 10 white eyeballs still in the bag...
- 01:40
But the question asks what are the odds of BOTH of these things happening...
- 01:44
...so when we cover two linked events, we multiply them to get the TOTAL odds...
- 01:49
...we have one over four times 10 over 23 to get 10 over 92 which reduces to 5 over 46.
- 01:57
So our answer is choice B.
- 01:59
Should we take a vote to make sure there's a consensus on the right answer?
- 02:02
Looks like the eyes have it.
Related Videos
CAHSEE Math: Algebra and Functions Drill 5, Problem 3. Solve the equation.
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...
