stupid BOS ( the actuall bos) (2 Viewers)

[dark_angel]

could someone plz calarify the difference between reliabilty and accuracy. I am having an extrememly hard time distiguishing between the two.

Lets say u have the sulfate content in fertiliser q.

how can u improve accuracy and reliability of the experiment

i have a vague idea only.

ALso, what is the EXACT DIfferece between Qualitative and Quantitaive analysis.

ALso, is the variable that u measure in an experiment the dependent variable (which i think is correct) or is it the independant variable.

ALso, what is the difference between an hypothesis and a conclusion? (is an hypothesis an educated guess ? )

BOS are freaking sad.

 

[freaking_out]

hmm...with the sulfate thingy, to improve accuracy u just repeat the experiment, and to improve reliability, u gotta tell me the method as to how u did it.

but basically reliability means, how well does ya experiment answers the aim, i.e can we really trust it to give us the correct amount sulfate content of fertiliser?

 

[dark_angel]

ic ic

 

[toknblackguy]

i'm not too sur efreakingout...
i agree with accuracy - just repeat it, and just more accurate equipment (eg scientered crucible)
but i thgouht validity was whether or not the experiment answers the aim...or maybe it's the same thing

the difference between quantitative and qualitative is that quantitative means via vcalculations, whereas qualitative means more theoretical

the dependant variable is the one you change as the experimenter, eg the amount of sulfate you use and the amount of Ba(NO3)2 you add. the independant variable is that which changes due to the changes in the dependant variable. eg if you add more reactants (dependant) then the independant preciptate will increase as a result

hypothesis is an educated guess, wehre you try to guess what will happen in the experiment. the conclusion is what you can draw based on observations in the results. eg, you could hypthesise that the preciptate form and be caught in the crucible. but most of the crystals pass through the filter thing cause they're too small (observatiosn in results). conclusion, the crystals..umm...whatever

hope it's right
frigid'll be on soon enough to clarify
cheers

 

[spice girl]

accuracy is a measure of validity

precision is a measure of reliability

i leeched this off the prelim notes i have, but basically you have two types of errors: systematic errors and random errors..

systematic error is how far off your average reading is from the true value. it's affected by how your experiment is designed. poorly designed experiments tend to have higher systematic errors, no matter how much you repeat it.

random errors is how far off each individual reading is from the average reading (also measured in terms of standard deviation). this is usually from poor technique such as spilling, incorrect reading, etc. You usuallu repeat the experiment to minimise the effect of random errors.

accuracy is a measure of how small the systematic error is

reliability is a measure of how small the random errors are.

 

[iambored]

qualitative - words
quantitative - numbers

 

[mon_mon]

isn't it just like quality and quantity?

 

[phenol]

think about in maths the function y = f (x)

for any x value u choose, the y value changes with it

so x is the independent variable (u choose) and y is the dependent variable (depends on how x changes)

 

[Constip8edSkunk]

my dog is fat - qualitative
my dog is 95kg - quantitative

EDIT: hypothesis is a statement, most likely a prediction or a proposal that you draw, which has not been validated by experimental evidence, (once it has, it becomes a theory)

conclusion, in the contexts of experiments, is basically what you can conclude from the results, with emphasis on answering the aim

 

[inasero]

hmm...with the sulfate thingy, to improve accuracy u just repeat the experiment, and to improve reliability, u gotta tell me the method as to how u did it

wrong!! just cos u repeat the experiment many times and get consistent results does not mean the resulats are sccurate...because the results could be consistently crap you know what I'm saying?

but basically reliability means, how well does ya experiment answers the aim, i.e can we really trust it to give us the correct amount sulfate content of fertiliser?

wrong again...reliability is how consistent your results are...how well they answer the aim falls under the definition of validity...eg in the sulfate prac you might measure how many bananas consumed while performing the experiment, and the results would be reliable, but not valid cos they have nothing to do with the aims of the experiment

 

[inasero]

my dog is fat

ehheh what dog?

 

[phenol]

hmm...with the sulfate thingy, to improve accuracy u just repeat the experiment

you are actually improving precision not accuracy

 

[Frigid]

could someone increase the timeout limit on the forums? it really pisses me off when i prepare a super-long answer (since he asked so many questions) and the forums had already logged me out so i lose the bloody 2 page post... >.<

 

[toknblackguy]

hahahahaha
bad luck frigid...perhaps type the stuff up in word and then copy across when done

 

[Frigid]

i wrote you an answer here.

 

[dark_angel]

Originally posted by Frigid
i wrote you an answer here.

wow thanks frigid, i finally understand this shit properly now.

btw we did do the alizarin red exp. but it was scraped becacuse teacher could not find the equivalence point