To be a cat is sufficient to be a mammal, but not necessary. Just because something is a mammal doesn't necessarily mean it's a cat, so "cat" is not necessary to be a mammal.
To be a mammal is necessary to be a cat, but not sufficient. If something is a cat, it is necessarily a mammal, so being a mammal is a necessary condition of being a cat. To say something is a mammal is not enough information to infer that is also a cat, so being a mammal is not sufficient to cat.
The example I always go back to is from elementary school: all squares are rectangles (sufficient) but not all rectangles are squares (necessary). Helps me remember, maybe it'll stick for someone else :)
Right now I am drinking coke (subset) a type of beverage (superset). Therefore If I am drinking coke (sufficient condition) I am having a beverage (necessary condition). Which negated is "If I am not having a beverage (necessary condition) than I am not drinking Coke (sufficient condition). Thus I do not have to be drinking coke to be having a beverage but if I am having a coke, I am having a beverage.
The incorrect statement of confusing sufficency for necessity would be "I am having a beverage, therefore I must be having a coke" because from our negation of the statement we know we DO NOT need to be having coke to be having
In my head sufficiency means that without a a doubt the information provided makes the claim true. Necessity means that there are certain conditions that must be met even if they don’t guarantee the claim to be true.
Ex:
info: to be a cat you must be a mammal
Claim 1: lassie is a mammal therefore lassie is a cat.
This is obviously not true there is not SUFFICIENT information to prove that lassie is a cat. Lassie meets the NECESSARY conditions to be a cat (being a mammal) but there is not sufficient info for being a mammal to guarantee that he is a cat.
Claim 2: Garfield is a cat therefore Garfield is a mammal
True. This can be proven true because there is SUFFICIENT info to say that Garfield is a mammal.
Generally the smaller subset will provide sufficiency for larger groups, and larger groups will provide necessity to be part of smaller subsets.
Right now, I’m drinking Yerba mate, a subset of tea, which is a subset of beverages.
If we're just looking at Yerba mate and tea, Yerba mate is the subset/sufficient condition, and tea is the superset/necessary condition. Similarly, when looking at tea and beverages, tea is the subset/sufficient condition, and beverages is the superset/necessary condition.
I don't have to be drinking Yerba mate to be drinking tea (sufficient). But if I am drinking Yerba mate, then I'm definitely drinking tea (necessity).
What helped me to understand this is looking at the visuals and telling myself necessary conditions starts with the superset, or an outer circle, and works its way in and sufficient starts with the subset, or an inner circle, and works its way out.
Earrings are sufficient to be jewelry, but not necessary (because jewelry could also be rings, necklaces, etc.). Jewelry is necessary to be earrings, but not sufficient (not all jewelry are earrings).
A way that is helping me remember is that in the circle diagram, the arrows move to the north from sufficiency to necessity. Therefore, south to north. Probably not applicable every time, though.
Your comment made me think of a trick to remember these ideas..!
In recap...
• Necessity = Superset ... Membership in a superset is necessary for membership in a subset, but not sufficient
• Sufficiency = Subset ... Membership in a subset is sufficient for membership in a superset, but not necessary
When imagining the diagrams from the lesson, in the case of necessity where we go from subset to superset, the arrow would be pointing upwards↑. This is the same movement from going from south to north, we go upwards. Necessity starts with an n just like north. So, when dealing with a relationship and you're imagining the diagram, if the arrow is going up ↑north, it's a necessity.
Vice versa for sufficiency. In a sufficient relationship, the arrows move downwards↓ from the superset to the subset. Basically, from north to south. Sufficiency starts with an s just like south. So, when dealing with a relationship and you're imagining the diagram, if the arrow is going down ↓south, it's sufficient.
I tried to explain this trick the best I could, I hope it may help others.
You're on the right track! To add a little more nuance, we can say:
Being a carrot is sufficient to being a vegetable, but not necessary.
Why? You don't need to be a carrot to be considered a vegetable. You could be broccoli or lettuce, for example. Nevertheless, if you are a carrot, you are automatically considered a vegetable.
Being a vegetable is necessary to being a carrot, but not sufficient.
Why? Just because you are a vegetable doesn't automatically mean you are a carrot. To be a carrot...you must be a carrot. Of course, if you aren't even a vegetable to begin with, like an apple or watermelon, there is absolutely no way that you could be considered a carrot
Being on earth is sufficient for being in the universe, but not necessary. Being in the universe is neccessary for being on earth but not sufficent. You can be on Mars or Pluto and still be part of the universe.
Playing basketball is sufficient to be playing a sport (because basketball is a sport). However, playing basketball is not necessary to be playing a sport (could be playing another sport).
Playing a sport is necessary to be playing basketball (because basketball is a sport). However playing a sport is not sufficient to be playing basketball (could be playing another sport).
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I think I'm understanding this part...
To be a cat is sufficient to be a mammal, but not necessary. Just because something is a mammal doesn't necessarily mean it's a cat, so "cat" is not necessary to be a mammal.
To be a mammal is necessary to be a cat, but not sufficient. If something is a cat, it is necessarily a mammal, so being a mammal is a necessary condition of being a cat. To say something is a mammal is not enough information to infer that is also a cat, so being a mammal is not sufficient to cat.
This was helpful, thanks! (:
thank you, you explained it better than I could understand the lesson lol
The example I always go back to is from elementary school: all squares are rectangles (sufficient) but not all rectangles are squares (necessary). Helps me remember, maybe it'll stick for someone else :)
That's a great example, will definitely be using that also. Thank you for sharing!
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I'm taking it in October too! We got this!!
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Right now I am drinking coke (subset) a type of beverage (superset). Therefore If I am drinking coke (sufficient condition) I am having a beverage (necessary condition). Which negated is "If I am not having a beverage (necessary condition) than I am not drinking Coke (sufficient condition). Thus I do not have to be drinking coke to be having a beverage but if I am having a coke, I am having a beverage.
The incorrect statement of confusing sufficency for necessity would be "I am having a beverage, therefore I must be having a coke" because from our negation of the statement we know we DO NOT need to be having coke to be having
a beverage.
A well written and top tier example. Thank you, my friend.
absolutely love the visual aid for understanding sufficient and necessary conditions. imagining them as a circle that has layers is super helpful!
I am so lost. I read this three times and some how reading it isn't the same as a video. Hopefully I won't confuse the rules...
In my head sufficiency means that without a a doubt the information provided makes the claim true. Necessity means that there are certain conditions that must be met even if they don’t guarantee the claim to be true.
Ex:
info: to be a cat you must be a mammal
Claim 1: lassie is a mammal therefore lassie is a cat.
This is obviously not true there is not SUFFICIENT information to prove that lassie is a cat. Lassie meets the NECESSARY conditions to be a cat (being a mammal) but there is not sufficient info for being a mammal to guarantee that he is a cat.
Claim 2: Garfield is a cat therefore Garfield is a mammal
True. This can be proven true because there is SUFFICIENT info to say that Garfield is a mammal.
Generally the smaller subset will provide sufficiency for larger groups, and larger groups will provide necessity to be part of smaller subsets.
Right now, I’m drinking Yerba mate, a subset of tea, which is a subset of beverages.
If we're just looking at Yerba mate and tea, Yerba mate is the subset/sufficient condition, and tea is the superset/necessary condition. Similarly, when looking at tea and beverages, tea is the subset/sufficient condition, and beverages is the superset/necessary condition.
I don't have to be drinking Yerba mate to be drinking tea (sufficient). But if I am drinking Yerba mate, then I'm definitely drinking tea (necessity).
yes exactly and also goated beverage choice
What helped me to understand this is looking at the visuals and telling myself necessary conditions starts with the superset, or an outer circle, and works its way in and sufficient starts with the subset, or an inner circle, and works its way out.
Am I correct:
subset: earrings
superset: jewelry
Earrings are sufficient to be jewelry, but not necessary (because jewelry could also be rings, necklaces, etc.). Jewelry is necessary to be earrings, but not sufficient (not all jewelry are earrings).
i think so really good example super helpful
Subset: Cake
Superset: Dessert
Being a cake is sufficient to be dessert, but not necessary.
Being a dessert is necessary to be cake.
Am I right?
Yes!
A way that is helping me remember is that in the circle diagram, the arrows move to the north from sufficiency to necessity. Therefore, south to north. Probably not applicable every time, though.
Your comment made me think of a trick to remember these ideas..!
In recap...
• Necessity = Superset ... Membership in a superset is necessary for membership in a subset, but not sufficient
• Sufficiency = Subset ... Membership in a subset is sufficient for membership in a superset, but not necessary
When imagining the diagrams from the lesson, in the case of necessity where we go from subset to superset, the arrow would be pointing upwards↑. This is the same movement from going from south to north, we go upwards. Necessity starts with an n just like north. So, when dealing with a relationship and you're imagining the diagram, if the arrow is going up ↑north, it's a necessity.
Vice versa for sufficiency. In a sufficient relationship, the arrows move downwards↓ from the superset to the subset. Basically, from north to south. Sufficiency starts with an s just like south. So, when dealing with a relationship and you're imagining the diagram, if the arrow is going down ↓south, it's sufficient.
I tried to explain this trick the best I could, I hope it may help others.
Superset: Soccer Player
Subset: World Cup
Necessary Condition: It is necessary to be a soccer player to play in the World Cup.
Sufficient condition:
Playing in the World Cup is sufficient grounds to being a soccer player
If you are not a soccer player, then you are not playing in the world cup
Superset: Fruit
Subset: Apple
Fruit is the necessary for the apple
its not necessary for a type of fruit to be an apple
Superset: Types of Dance
Subset: ballet
Being a type of dance is necessary for ballet.
It is not necessary for a type of dance to be ballet. (It could be jazz or hip hop)
subset: student at harvard
superset: student
Being a student is necessary to being a student at Harvard
But it is not necessary to be a student at harvard to be a student
How is my example:
Superset: Vegetable
Subset: Carrot
Being a carrot is sufficient to be a vegetable.
Being a vegetable is necessary to be a carrot.
You're on the right track! To add a little more nuance, we can say:
Being a carrot is sufficient to being a vegetable, but not necessary.
Why? You don't need to be a carrot to be considered a vegetable. You could be broccoli or lettuce, for example. Nevertheless, if you are a carrot, you are automatically considered a vegetable.
Being a vegetable is necessary to being a carrot, but not sufficient.
Why? Just because you are a vegetable doesn't automatically mean you are a carrot. To be a carrot...you must be a carrot. Of course, if you aren't even a vegetable to begin with, like an apple or watermelon, there is absolutely no way that you could be considered a carrot
Superset: Sports
Subset : Football
Playing football is sufficient to believe you play sports.
Playing a sport is not sufficient for you to play football. (because it could be basketball, baseball, etc)
Playing a sport is necessary for you to play football.(you can't play football without playing a sport)
Superset: Employee
Subset: janitor
Being a janitor is sufficient to being an employee
Being an employee is necessary to be a janitor
Now I'm lost.
Subset: Cookies
Superset: Desserts
Being a cookie is sufficient for being a dessert
Being a dessert is necessary to be a cookie
SUBSET: Hennessy
SUPERSET: Cognac
Hennessy is sufficient to be a cognac, but not necessary. Cognac can be Remy Martin or more, but not necessary Hennessy.
superset: Universe
subset: earth
Being on earth is sufficient for being in the universe, but not necessary. Being in the universe is neccessary for being on earth but not sufficent. You can be on Mars or Pluto and still be part of the universe.
#feedback for the web managers - when you pause the videos the screen goes blank / white making it very difficult to take notes.
subset: television
superset: electronic
being a television is sufficient to be an electronic.
being an electronic is necessary to be a television.
Subset: basketball
Superset: sports
Playing basketball is sufficient to be playing a sport (because basketball is a sport). However, playing basketball is not necessary to be playing a sport (could be playing another sport).
Playing a sport is necessary to be playing basketball (because basketball is a sport). However playing a sport is not sufficient to be playing basketball (could be playing another sport).