Translation:Excuse me, do you have a bigger one?
The sentence is shortened by removing the object. It's really 大的（东西）. Just like in english you can say "a bigger one" when really you mean "a bigger shoe" or something like that. This sentence would be said to a person who can see or already knows what the thing (东西) is.
I think many of us would really appreciate an explanation of the structure of this sentence from a native or advanced Chinese speaker. A direct translation of this sentence into English would give something like "Excuse me, do you have big a little bit's" which of course makes absolutely no sense, so it should be understandable that this sentence is confusing to anyone who isn't very familiar with Chinese.
In this usage of 一點兒 it follows an adjective, in this case 大 and is used in comparison, so in this case it means "a bit bigger". 慢一點 means a bit slower.
Don't know where they get the "one" from, and 一点儿 means "a little bit", the yī does not necessarily stand for 'one' in the expression.
If you want something that is more often said in English as an equivalent it would be, "Excuse me, do you have a bigger size". "Bigger one" is pretty colloquial. If it was a pair of something we'd say 'bigger pair'.
The problem with this course is that sometimes they choose very literal translations, almost word for word, and other times they just invent the English equivalent. We get caught out in the middle trying to guess which approach they are going to take.
The "one" is a substitute for the unknown object, which the speaker is probably holding or pointing to. In Chinese the object is omitted because it is obvious from the context, but in English we don't omit it, so the English translation adds in a generic object.
Maybe what you are really saying is that in the place you come from the English sentence is not natural or common. But it is natural and common in other places; I live in one of those places where this would be normal. So I hope that Duolingo can support a natural answer option for people from all places where English is spoken natively.
有点儿 (a shortening of 有一点儿) is used before an adjective to indicate "a little bit" of the adjective. It is only used to express negative or undesirable things. For example: 考试有(一)点儿难。Tests are a little hard. (有一点儿 modifies 难.) That is different from 一点儿. 一点儿 is used before a noun to mean "a little bit" of the noun. For example: 我想喝一点儿茶。I want to drink a little tea. (一点儿 modifies 茶.) 一点儿 can also be used after certain adjectives to mean "a little more" of the adjective. 我要大一点儿的鞋子。I need shoes that are a little bigger. (一点儿 modifies 大.)
请问 means "May I ask?" and NOT "Excuse me". But you will not let me progress until I submit to your pedagogic translation. If you are buying an apple or a watermelon, you may ask for "a bigger one" but if you are buying a pair of shoes or a dress, you would ask for a "larger SIZE" and definitely not "a bigger one".
In US English, we say "excuse me" when we approach unfamiliar people to ask them questions or say something. Whether it is a waitress, shop keeper, or a complete stranger, that is the correct way to politely request someone's attention before you begin to speak. I live in New York City, no one says "may I ask" before they start to talk to someone.
I've noticed that this course uses 你们 when a person asks a question within a restaurant or business. Even if they are probably talking directly to a single employee, they refer to the employee as the business itself with multiple workers. We typically don't do this in English. Only some US Southerners use "y'all" in a similar way to the Chinese.
你们有什么饮料？= What drinks do you have?
Yes, asking a question of staff in a restaurant or shop it is normal in my experience to say 你們 rather than use a singular.
Exceptions are when the shop is obviously just a single person, like a roadside stall, or your question relates to the person you address specifically instead of the store generally.