Statistical methods, as used in the design and interpretation of chcmical experimentation, arc not a substitute for common sense or for what scientists refer to as scientific judgement; they rather constitute an objective aid to judgement. In view of the mcticulousncss exhibited by scientific workers in die purely technical aspects of dicir experiments it seems appropriate to devote some thought to two further and no less important aspccts of experimentation: its design and the final interpretation of its outcomc. Very often the experimenter designs the experiment as it proceeds, acting on a moment's intuition. Similarly, the interpretation or a rudimentary study of data, the latter consisting in many cases in ranking studied clTccts in accordance with their observed disturbances caused by experimental and systcmctic errors. Naturally, even the most experienced worker is subject to an occasional intuition. Therefore natural, and actually borne out by (he facts, is the assumption that many experiments could have resulted in more conspicuous and sharper constructed plan.
In taking cognizance of the unavoidable experimental errors, rather than in ignoring them or dismissing them as negligible, and in attempting a mathematical study of the avoidance or the correction of systematical errors, statisticians have succccdcd, to a ccrtain extent, in offering some objective criteria which are invaluable in these situations. One of the important by-products of these methods is an estimate of the quantity of experimental work that is necessary for obtaining sufficient factual proof for a scientific hypothesis, such an estimate being more objective than the guessing technique often used. But among the most important contributions of statistical methodology to scientific experimentation is the possibility of clearly separating the effects of various variables under study as well as the interactions of these variables with regard to the measured quantities, from the data resulting from a complex experiment. Hardly can it be denied that this requires careful planning. Even before the experiment is started, the various possible types of results must be hypothctically considered from the point of view of the questions under study.
Words and Word-Combinations to Be Memorized
aid, by-product, common sense, construct, construction, contribution, correction, criterion, data, design, error, experienced, the extent to which, mathematics, negligible, objective, occasion, offer, point of view, possibility, proof, refer to as, statistical, statistics, substitute, succeed (in), sufficient, sufficiently, in view of
Ex. 5. Give the Russian equivalents for the following:
be a substitute for, an aid to judgement, in the purely technical aspects, it seems appropriate, the design of the experiment, act on a moment's intuition, be subject to, ignore experimental errors, the correlation of errors, an objective criterion, obtain sufficient factual proof, guessing technique, result from a complcx experiment, require careful planning, consider from the point of view of
Ex. 6. Give the English equivalents for the following:
здравый смысл, ввиду многих ошибок, объяснение результатов эксперимента, планировать эксперимент по мерс его протекания, изучение данных, в соответствии с наблюдаемыми фактами, опытный исследователь, естественное предположение, приводить к экспериментальной ошибке, избегать систематических ошибок, статистикам удалось сделать, быть бесценным, предложить объективные критерии, один из побочных продуктов, изучаемые переменные, взаимодействие переменных, до начала эксперимента, рассматривать с точки зрения
Ex. 7. Fill in the blanks with articles where necessary.
1. Statistical methods arc not... substitute for... common sense. 2. Two important aspects of... experimentation arc its ... design and ... final interpretation of... results. 3. Very often ... experimenter acts on ... moment's intuition. 4. Experimental work is ncccssary for obtaining ... sufficient factual proof for... scicntific hypothesis. 5. Before... experiment is started it is ncccssary to consider ... various possible results hypothetical ly.
Ex. 8. Give the synonyms for the following:
help, show, more, facts, supposition, take notice of, amount, demand, begin, kind
Ex. 9. Give the antonyms for the following:
first, the former, contrary to, inexperienced, regular, take into account, insufficient, the same, simple, after, finish
Ex. 10. Translate the sentences into Russian.
1. Students of chcmistry have to perform a number of experiments studying the properties of any substancc and so do students of geology. 2. Considered as isotopes arc atomic species having the same number of neutrons but different mass numbers. 3. Not only docs chlorinc unite with free hydrogen, but it has the ability to take hydrogen from hydrocarbon compounds. 4. Only upon heating above 500°C docs zinc burn with a greenish flame, yielding zinc oxide. 5. No sooner is a solid brought into contact with liquid in which it can dissolve than a certain amount of it passes into solution. 6. The first phase consists of cxccss of phenol and a small quantity of water, so docs the second one. 7. One liquid layer docs not contain water, nor docs the other. 8. Included in this table arc densities of liquid and vapour. 9. Not until 1869 was this theory put forward. 10. Neither should wc forget to check the purity of the substanccs to be handled. 11. Nowhere is it so important to have skilful hands as in a chcmistry laboratory. 12. Never is it so important to think about style as in writing a textbook. 13. Never has more accurate result been obtained. 14. He was always ready to answer any question and so was his friend. IS. Hardly had wc heated the test-tube several minutes when an explosion suddenly happened. 16. Important for this conclusion is the arrangement of atoms in the molcculcs. 17. Correlative with the hypothesis arc the results of the latest series of experiments. 18. Great arc differences in selectivity between intermediates. 19. Plotted in Figure 5 is the variation of selectivity.
Ex. 11. Translate the sentences into English without using a dictionary.
1. Очень важными в аналитической химии являются статистичсс- кие методы. 2. Едва ли можно сказать, что планирование экспсрн- мента — простое дело. 3. Объяснить конечный результат реакции бывает нспросто и опытному химику. 4. Ученым удалось выработать некоторые методы, чтобы избежать ошибки при проведении экспериментов. 5. Объективными критериями правильности научной гипотезы можно считать только факты.
Ex. 12. Answer the following questions:
1. In what fields of analytical chcmistry can statistical methods be used? 2. What important aspects of experimentation should be taken into account? 3. What is the role of intuition in experimentation? 4. What must be the attitude to errors? S. What is regarded as the most important contribution of statistical methodology to scientific experimentation?
Scction II
Упр. 1. Назовите значения следующих интернациональных слов:
fundamental, balance, operation, utilize, limitation, intuitive, extreme, delicate, calibration, specialize, actually, visualize, ordinary
Упр. 2. Проверьте, помните ли вы значения следующих слов; если нет, обратитесь к словарю:
tool, capability, realize, take for granted, precise, ratio, yield, tend, teeter-totter, pendulum, upright, axle
Text 34 В
Прочтите текст про себя (контрольное время чтения — 2 минуты). Fundamentals of the Analytical Balance
Of great importance in the laboratory is the analytical balancc, one of the most common laboratory tools. Its usefulness increases when the chcmist understands its operation well enough to utilize the full capabilities and to realize the limitations of the balancc.
Some chcmistry students do not become proficient in the use of the balancc, understandably, they arc concerned with so many other and complex instruments and problems. The balancc is taken for granted. It may be that, because balances have been used for so many centuries, intuitive knowledge about them is assumed. At the other extreme are those who know there is something precise and presumably delicate about a balancc, and so they avoid using one if possible. This is unfortunate bccausc mass, along with length and time, is a fundamental measurement. An example is the use of the balancc to prepare standards for the calibration of more specialized instruments. Another important thing about a balancc is its high ratio of capacity to sensitivity. Few measurements will yield as many significant figures as weighing on an
analytical balancc. Results to six significant and cxact figures arc ordinary.
Those who have learned about balances by an intuitive process tend to think of them as tectcr-tottcrs. Actually a balancc is a compound pendulum with complications. The essentials of the operation can be understood easily, however, by visualizing an upright wheel free to turn on a fixed axle...
Упр. 3. Передайте основное содержание текста в нескольких предложениях.
Упр. 4. Какое слово в тексте означает «искусный, умелый»?
Упр. 5. Найдите в тексте ответы на следующие вопросы:
1. When docs analytical balancc bccomc a useful tool in the laboratory? 2. What is the attitude of students to the use of analytical balancc? 3. What measurements arc regarded as fundamental? 4. What is the characteristic feature of analytical balancc? 5. What is the design of the analytical balancc?
Упр. 6. Закончите следующие предложения:
1. Analytical balancc is... 2. Chemistry students arc concerned with... 3. Some students avoid using a balancc bccausc... 4. The balancc can be used to prepare standards for... S. Usually, a balancc is thought to be...
Section III
Ex. 1. Make up short dialogues according to the example. Example
— Can 1 help you?
— Yes. I'd like some information about foreign journals on chcmistry in this library.
— What field of chemistry arc you interested in?
— Nature compounds.
— Let's use the computer, we'll find all the information you need.
Ex. 2. Respond to the following statemets:
1. Statistical methods arc used not only for the design of experimentation. 2. To my mind, intuition is not important for chcmists. 3.1 don't think the balancc is the most essential tool in a chcmical laboratory, there arc many others.
Ex. 3. Give detailed answers to the questions.
1. What methods arc used in analytical chcmistry? 2. What must students be able to do in a laboratory? 3. What aspects must be taken into account in planning experiments?
Ex. 4. Discuss the following topics:
1. Interpretation of Experimental Results.
2. Designs of Modern Analytical Balances.
3. How to Avoid Errors in Experimentation.
4. How to Estimate Experimental Errors.