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Chapter Ex Empty numbers
Paradox
Scientists make observations to perhaps three or four digits，and proce the results on an eight-digit calculator．Careful scientists then discard meaningle digits．They also use numbers and numerical words with care．But some writers use words with a precision corresponding to only one significant digit!Here are examples of these and other aberrations．
Doubtful ratios
The phrase‘3 times more than’means‘4 times as much as'．If this surprises you，extrapolate down to once more than，which obviously means twice as much as．Many readers take‘times more than’to mean the same as‘times as many as’，so the former expreion is best avoided．What does‘4 times Ie than’mean?‘Once more than’means ‘twice as much as’，so‘once le than’must mean‘none’．Hence‘4 times le than’seems to mean‘minus 3 times’．
‘Every second baby is a boy’is not true．‘One in every two babies is a boy’is no better．By omitting‘every’we remove the absurdity．The words‘on average’might be added．‘Three in every 10 plants were diseased’implies a regularity that seem unlikely．A fine example [yes，it is genuine] that shows the absurdity is‘8½ people out of every 10．．．’．One’s mind tries to visualize ½ of a person instead of paying attention to the statistics．Better would be‘17 out of 20’or‘more than 8 out of 10’．
‘Decimate’originally meant kill every tenth man．Wise writers apply discretion in using the term for the elimination of more than a tenth．
Dilution
The term 1:4 is a ratio and is read as‘one to four’．For example,'the ratio was 1 sheep to 4 goats’means 1 sheep in 5 goats．not 1 in 4．The meaning of 1:4 is different from that of 1/4，which has the sense of ¼．Some people read 1:4 as 1 in 4 and write‘diluted 1:4’when they really mean that the final volume was 4．The‘1:4’is then wrong．Are you unconvinced? Then consider the term 1:1．which cannot mean 1 in 1．If you made 1 vol of solution up to 4 vols by adding diluent，then for clarity’s sake write that．‘Diluted 1 in 4’or even‘1→4’may be suitable for most purposes．If the exact dilution is important，you might write‘1 vol solution A was diluted to 4 vols by adding solution B’．Bear in mind that 1 vol fluid A(e．g．ethanol or H2S04)added to 1 vol fluid B(e．g．water)may not produce 2 vols of mixture．
(1)Are all your numbers correct?
If‘adviser’is mipelt，a subeditor can change that．If 27 appears for 21 a context may not help, so we are confused．Editors’time is wasted over wrong numbers actually detected，but the total of errors is unknown．In a table，nobody but the author can check the values．Draw a bar through each hand-written 7 to distinguish it from other characters．
Statistics
Standard deviation and standard error have often been confused．Yet they are the very quantities that are supposed to indicate precision!So take care that there can be no doubt and do not omit the M from S．E．M．
When n is small，these statistics have only little meaning．If an author offers statistics based on，n = 2．the meage conveyed to readers is that of desperation rather than useful discovery，and we may doubt the claims!An often-seen phrase is‘most probably’，which means highest poible likelihood．i．e．P = 1．Frequent use of‘most’debases its meaning．
Phrases to avoid
‘Cages were built between 1988 and 1989．’Quick work indeed，for the interval is infinitely small．
‘Twice the size’is sometimes written for twice the dimension．Because of poible misunderstanding，the former term should be used warily or not at all．If a picture’s dimensions are doubled，its area is quadrupled．A surface 3 m square has an area of 9 m．Some readers may not knowthat．Write 3 m × 3 m．
Do not write 3-400 if you mean 300-400．
‘A plate 75 × 90 mm’is not scientific．Write 75 mm × 90 mm． An experiment repeated 3 times iS done 4 times．If you have doubts, consider‘repeated once’．‘Repeated again’might be considered tautological．
‘Divided by a third’is best avoided．If the reader iS not interested in decoding．the information is lost．
‘A certain amount’usually means an uncertain or unspecified amount and is too vague for scientific reporting． A speaker described a humming bird that lives in high mountains in Equador．He told us‘To conserve energy the bird’s temperature falls to half at night’．What is half a temperature? ‘Nearer 40 than 30’tells us only little: any number>40 is nearer 40 than 30．We know what the speaker means，but should the language not have been more precise? Percentages
The sign％indicates a pure fraction without units．The present tendency of using terms other than percentage for concentrations is admirable．A writer who describes a concentration as 5％and then writes‘it rose 2％’leaves you to gue whether 2 percentage units or× 1.02 is meant．Percentages are best reserved for comparisons．They must be clear．Replace‘150％more than’by 2 ± times．What does‘250％ lower than’mean? Do not write‘g／L of KCI’if the solution iS not per Iitre of KCl but of KCl per litre．Equally unscientific，though common，is the note that 2 mg／kg of a drug were given．Write‘2 mg of drug per kg’or‘drug(2 mg／kg)’．The argument also applies to‘p．P．m．C02’．
Do your readers demand too much?
Perhaps you think these comments are pedantic．Some may be．But scientific reports，written or spoken，should reflect the precision of the experiments．Numbers and values submitted to editors or presented at meetings are sometimes hardly better than‘umpteen zillion’or‘every so often’
