Notifications
Clear all

Rounding....what say you?

25 Posts
17 Users
33 Reactions
1,042 Views
CV-Nevada
(@cv)
Posts: 203
Supporter
 

@thebionicman 

Equal Opportunity Explosives 😊 LOL!

 
Posted : March 18, 2025 5:36 am
1
mathteacher
(@mathteacher)
Posts: 2098
Member
 

Just maddening. Where did I fail? (Don't answer that!)

It's just fundamental that a measurement like, say, 21.50 feet, represents an exact measurement that is somewhere between 21.495 ft and 21.505 ft. Whether the exact measurement, if we could by some magic know it, is 21.49888756 feet or 21. 503998743 feet or any number between the above bounds is immaterial.

The even-odd rounding schemes are used to improve the odds that sums of rounded numbers won't produce rounding errors.

If a published measurement is, say, 100 feet, and I measure the distance to be 99.6 feet, there is no observable error. Had the published measure been 100.0 feet, then a measurment error exist.

Of course, no one would expect a bureaucrat to understand, so we're all on our own when we deal with them.

 
Posted : March 19, 2025 5:46 pm
2
rankin_file
(@rankin_file)
Posts: 4017
Member
 

I concur this the artillery round off- 82C used to get this in their training with using TM6-235  the 6 place log tables - dividing an even number by 2 is cleaner….

 
Posted : March 20, 2025 3:59 pm
thebionicman
(@thebionicman)
Posts: 4489
Supporter Debater
 

@mathteacher For positions, Idaho requires an explicit statement. You have to remember our maps are prepared and used by a diverse crowd. Some in that crowd have large buckets, full to the brim with knowledge, others have incredibly small buckets, full of holes and rarely used...

 
Posted : March 21, 2025 11:16 am
1
mathteacher
(@mathteacher)
Posts: 2098
Member
 

@thebionicman 

Understood. Being sticklers on rounding grading is one way that physics teachers get students' attention.

Measurement accuracy and precision are so much improved since the time that a lot of surveying was done that we have to decide whether to use old standards or current ones in any particular case.

Perfection is hard to achieve.

 
Posted : March 21, 2025 12:47 pm

Page 2 / 2