ShmoopTube
Where Monty Python meets your 10th grade teacher.
Search Thousands of Shmoop Videos
Algebra II Videos 107 videos
Data doesn't do us much good if we can't interpret it. Ever snuck into a CPA's office while he slips out for a coffee break and tried to decipher o...
Statistics, Data, and Probability II Drill 4 Problem 2. Based on the graph, which statement is most likely to be supported by the data?
Pre-Algebra: Sampling Methods 1865 Views
Share It!
Description:
If you're looking for tips on how to score more free samples at Yogurtland, you've got the wrong video.
Transcript
- 00:04
Sampling Methods, a la Shmoop.
- 00:06
Ten days after setting sail from London with his…questionably hygienic…crew… [Captain Cornelius with his crew on a ship]
- 00:11
…Captain Cornelius discovered a parchment, reading:
- 00:14
"On the next full moon, Cornelius sleeps with the fish."
- 00:21
… Captain Cornelius created a poll to see if the crew was planning a mutiny. [Cornelius designing a poll on a parchment]
Full Transcript
- 00:26
He spent the better part of a month pondering the benefits of random sampling versus stratified sampling.
- 00:32
In random sampling, the polltakers would be chosen at random… [A roulette wheel spinning]
- 00:35
…each sample having an equal chance of being chosen.
- 00:39
However, the Captain Cornelius remembered that 20% of the crew were British royal navy men…
- 00:44
… while 80% of the crew were pirates. [A UK flag and a Pirate flag on the ship]
- 00:47
This seemed like some important information about the crew’s subpopulations, or strata.
- 00:53
In a stratified sampling, 20% of the polltakers would be made up of navy men while
- 00:58
80% would be pirates.
- 01:00
By taking samples proportionate to the crew’s subpopulations…
- 01:05
…the likelihood of accurate information is increased. [Cornelius swimming with sharks]
- 01:08
Well of course, he could have also used Systematic Sampling…
- 01:12
…where he might have lined up all 300 crew members and then just polled every tenth guy
- 01:17
to get a 10% sample. [Crew of men selected in systematic sampling]
- 01:19
Or he could have used Convenience Sampling, where the captain would have
- 01:23
simply polled those crew members who were within shouting distance… [Cornelius shouting and crew members appear]
- 01:26
…so he wouldn’t even have to get out of bed.
- 01:28
But he knew that stratified sampling would be the best option here...
- 01:31
…because he knew certain characteristics about the crew that could change
- 01:35
the results if the poll were conducted in a different way.
- 01:39
In the end, Captain Cornelius succeeded in collecting conclusive evidence that a mutiny [Cornelius walking the plank on the ship]
- 01:44
was indeed being planned.
- 01:45
Maybe he’ll be able to share the results of his poll with Davy Jones. [Cornelius thrown off the plank into the sea]
Related Videos
Statistics, Data, and Probability I: Drill Set 3, Problem 4. How many different avatars can be created based on the given options?
Statistics, Data, and Probability II Drill 3 Problem 2. Which two sports together make up for the preferences of more than half of all those w...
Statistics, Data, and Probability II Drill 3 Problem 3. One hundred twenty of those who were asked preferred what sport?
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...