Math Is Fun Forum

paulb203

Member

Registered: 2023-02-24

Posts: 261

Error Intervals

Sally used her calculator to work out the value of a number y
The answer on her calculator display began;
8.3
Complete the error interval for y
*
Does ‘began’ imply there is more to come after the 3?
Or could 8.3 be the answer on her calculator (could it begin AND END with 8.3?)

I’m thinking it implies it could be either, i.e, it might be 8.3, it might be more, so...
The answer on her calculator could be;
8.3
8.31
8.301
8.27685
8.999999999999999994
Etc, etc.
So...
The error interval is;
Equal to or greater than 8.3
Less than 8.4
?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,524

Re: Error Intervals

I think you've arrived at the right answer.

What is 8.27685 doing in your list?

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

phrontister

Real Member

From: The Land of Tomorrow

Registered: 2009-07-12

Posts: 4,860

Re: Error Intervals

I suspect that rounding might come into this...

I've never heard of error intervals, but rounding is uppermost in my mind atm because I'm working on a tricky problem where rounding is critical in finding solutions.

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"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

paulb203

Member

Registered: 2023-02-24

Posts: 261

Re: Error Intervals

I think you've arrived at the right answer.

What is 8.27685 doing in your list?

Bob

Thanks. Oh yeah, I forgot it began with 8.3! 8.999999.... shouldn't be there either!

paulb203

Member

Registered: 2023-02-24

Posts: 261

Re: Error Intervals

I suspect that rounding might come into this...

I've never heard of error intervals, but rounding is uppermost in my mind atm because I'm working on a tricky problem where rounding is critical in finding solutions.

Thanks. Ah, they are related to Bounds (upper bound/lower bound). Must be a UK thing. Rounding is the significant feature, but truncation is also a part of it.