What to know about laboratory report writing

How to write a Laboratory experiment report

September 20, 2012

Format of a laboratory report

General formatting

The body of the document should all have a font size of 12 point preferably times new roman or courier; all text should be double spaced, including the list of references. Margins should be 1 inch all around. Page numbering begins on the title page and should be centered at the bottom of each page (American sociological Association, 2009). Paper should be 8.5 by 11inches A4. Margins should be 1.25 left and right; 1 inch top and bottom According to Knisely, 2005, the font should be 12 point (points to the inch). And the typeface should be times new roman. All symbols used in the paper should be from word processing software and not hand written. The pagination should be Arabic numerals and inserted on the top right of each page except the first (Knisely, 2005). The page number is flush to the right margin; every page should be numbered, including the table. The page header is all in caps and can be no more than 50 characters, including spaces (Schwartz et al., 2012). The paper should have a double spacing and 0.5 inch double spacing for a new paragraph (Knisely, 2005). There should be only one space after punctuation marks including commas, colons, semicolons, punctuation at the end of sentences, periods in citations and all periods in the reference section. Arabic numerals are used correctly to express numbers that are 10 or greater; numbers that immediately preside a unit of measurement; numbers that represent times, dates, ages, participants, samples, populations, scores or points on a scale; and numbers less than 10 when those numbers are compared to a number greater than 10. Words are used correctly to express numbers less than 10 and numbers at the beginning of a title, sentence or heading (Jackson, 2009)

Paper format

A paper consists of sections and possibly subsections. There is rarely any need to break the subsections into sub-sections. Don’t break text into small blocks; three headings on a page are too many. Headings below the subsections should be paragraph leads, not lines by themselves.  Headings may or may not be numbered. It’s preferred to use only two level headings, major and minor and to only number major headings. Major and minor headings are clearly distinguished by font, size, or placement (Zobel, 2004). Each subheading should be boldface and flush left, and it appears on its own (Schwartz et al., 2012). The first heading should be capital, the second should be bold and the third should be in italics (UN, 2003). Heading one should be 14 point, heading two should be 13 point and heading three should be 11 point. There are generally three level headings in every chapter of a paper, i.e. middle heading; as the first level, left side heading as the second level and paragraph heading as the third level (Calmorin and Calmorin, 2007). The first level heading should be: all capital centered or left justified. The second level heading should be italics, upper and lowercase, centered or left justified (American sociological association, 2009). Align headings for abstract, introduction, materials and methods, results, discussion, and references on the left margin or centre them. Use consistent format for capitalization. No section should be started on a separate page unless it works out that way coincidentally (Knisely, 2005)

Title page; there should be a title and byline, name of the institution and word count. One may also include the lecturers/instructors name, the class and date. All the information should be centered on the page both horizontally and vertically. Page numbers should be at the top right corner of each page (American sociological association, 2009). The title page should have a title, authors (your name first, lab partner second), class and date (Knisely, 2005).The title should mention both the independent and dependent variables and the relationship that was demonstrated in the study (Emerson, 2005). The title page or cover page should have the name, course and section, instructors name and date of submission (O′day and Bunniak, 2012) the title should be no longer than 12 words, double space everything. No course number on title page unless specifically instructed to do so (Schwartz et al., 2012).

Abstract; one should centre the title “Abstract,” one inch from the top and a double space inserted after the title before beginning the abstract. The entire document should be summarized in the abstract and therefore the abstract should be written last after the whole document .The abstract should be in a block form, and single paragraph. It should be between 150 and 200 words and shouldn’t exceed 960 characters, including punctuation and spaces (American sociological association, 2009). The abstract shouldn’t be indented and should be no longer than 120 words (Schwartz et al., 2012).

Introduction; under this section, the title should be repeated and centered on the first page of text. One double space below the title, begin the introduction/literature review. This section states the problem under study gives background information and summarizes past research. All the variables involved in the experiment or study should be defined in this and an integrated summary of the literature reviewed. At the end of the introduction, the hypothesis should be stated (American sociological association, 2009). The introduction doesn’t require a heading, should be about 250words, use APA format for all references in the text and should end with the hypothesis or research question (Emerson, 2005). The introduction contains the statement of hypothesis or problem, review of literature and the methods used to prove hypothesis/solve the problem (O′day and Bunniak, 2012)

Materials and Methods; A detailed description of the procedures followed should be written under this section. One should give a description of the participants involved in the research study, provide a list and description of materials used and explain the research design and procedures followed (American sociological association, 2009). The heading should be centered. The procedure section should always be written in the past tense and with grammatically correct whole sentences without lists or notes (Emerson, 2005). This section includes the summary of methods employed as well as additional information/flow charts. It explains what one did and it’s always necessary to refer to the laboratory manual. Minor and major changes to the lab manual procedures should also be detailed in this section (O′day and Bunniak, 2012). The phrase et al. is used only when there are three or more authors. The word participants is used instead of subjects. The ampersand (&) is used in citations within parentheses and the word and is used in citations outside parentheses. The word while is used only to indicate events that take place simultaneously. Terms that are abbreviated are written out completely the first time they are used and then always abbreviated thereafter (Jackson, 2009)

Results; under this section the findings should be reported and the results of the experiment provided without an interpretation or an attempt to explain them - save the interpretation for the discussion section. One should however state whether or not the results support the hypothesis (American sociological association, 2009). The figures and tables should be incorporated into the text and as close as possible after the paragraph where they are first mentioned. Use descriptive titles, sequential numbering, and proper position above or below visual (Knisely, 2005). The table title should be in italics and there should be no vertical lines (Schwartz et al., 2012).

Discussion; the discussion heading should be centered and boldface. Usually the first paragraph of the discussion section reports the study’s major finding (Schwartz et al., 2012). Under this section, one should compare results that have already been reported in previous studies with the results of the present study. The consistency or inconsistency or the results with findings of the other studies should also be explained. Discuss whether the results support or refute your hypothesis and it is appropriate to give interpretation or explanation here (American sociological association, 2009). The discussion should have a centered heading, use a past tense when dealing with particulars of results and a present tense when dealing with implications and conclusions. One should begin with description of the results and end with a concluding summary (Emerson, 2005). The discussion part should also include the interpretation of results in terms of the hypothesis, comparison with literature, literature citation, comments on nature or cause of anomalous data, suggestions for improvement in design, suggestions for future experiments the conclusion. The conclusion should be part of the discussion or stand alone as conclusions. Normally this part consists of succinct statements about what the work has shown and any conclusion reached should be based upon the hypothesis one started with in the introduction (O′day and Bunniak, 2012).

References; an alphabetical reference list that includes every citation in the text should be supplied. Center the title, “References,” on a new page and begin the entries one double space below the title. Entries are made with a hanging indentation; the first line is flush left and further lines are indented five spaces. Double space the entries. Provide the following general information in an entry: author’s name, publication date, title or the work, additional information (e.g. volume number, type of electronic media etc), and page numbers (American sociological association, 2009). For the citation-sequence system one should make a numbered list in order of citation or if one uses a name year system then the list of references should be in alphabetical order by the first author’s last name. Use a hanging indent to separate individual references (Knisely, 2005). The internet reference should have a date when the article was posted and when the date is not defined use n.d in parentheses. The actual name of the webpage should be in italics, followed by the complete URL provided so that the reader can access the same materials you did (Schwartz et al., 2012).

Appendix; Place the appendix section after the reference list. Place the detailed information that would be distracting to read in the text such as tables, charts, graphs, or proofs, in the appendix. Identify the appendices with a capital letter in the order they appear in the other portions of the document. Place each on a separate page, double spaced, and with indented paragraphs (Knisely, 2005).

Assembly, place pages in order and staple on the top left (Knisely, 2005).

Some explanations to the commonest experimental terms

Error

The term error is used to refer to deviation from the intended level of a construct, with the measure used as a manipulation check assumed to have been validated (Viswanathan, 2005). Experimental error is the difference between the observed response for a particular experiment and the long run average of all experiments conducted at the same settings of the independent variables or factors. Errors can either be bias error in which case the error remains constant or changes in a consistent pattern over the runs in an experiment design or random error in which case error changes from one experiment to another in an unpredictable manner and average to be zero (Lawson, 2010).

Standard deviation

Standard deviation provides a measure of the typical or standard distance from the population mean i.e. (X- µ) and therefore must have a value somewhere between the largest and the smallest deviation scores. As a rule of thumb, the standard deviation should be about one-fourth of the range. It’s thus the square root of the variance (Gravetter and Wallnau, 2011). Its denoted by Ơ and the formula is Ơ = √ ∑(x- µ) ² /N (Black, 2011)

Standard error

Standard error measures the standard distance between a sample mean and the population mean, (M- µ). The standard error provides a measure of how much distance is expected on average between a sample mean (M) and the population mean (µ), (Gravetter and Wallnau, 2011).

  

Range

The range is the difference between the largest and smallest observations in the data set. The range though provides a misleading measure of spread if there are outliers. The inter-quartile range thus can be used to forego the effect of outliers (Petrie and Sabin 2009)

Degree of freedom

The concept of degrees of freedom represents the number of values in a set of data that are free to vary after certain restrictions have been placed upon the data (Sheskin, 2003)

Variance

Variance is defined as the mean of the squared deviation and it’s computed exactly the same way you compute any other mean. I.e. find the sum and then divide by the number of scores

Variance = mean squared deviation = sum of squared deviations/ number of scores

The sum of squared deviation SS = ∑(X-µ) ² where X is the score and µ is the mean. (Gravetter and Wallnau, 2011). The variance is the average of the squared deviations about the arithmetic mean for a set of numbers (Black, 2011). While according to Petrie and Sabin 2009, the variance is one way of measuring the spread of the data by determining the extent to which each observation deviates the arithmetic mean. Clearly the larger the deviation the greater the variability of the observations.

Coefficient of variation

Is a statistic that is the ratio of the standard deviation to the mean expressed in percentage and is denoted CV. Is a relative comparison of a standard deviation to its mean. It can be useful in comparing standard deviations that have been computed from data with different means.

CV= Ơ / µ (100). Where Ơ is the population standard deviation (Black, 2011)

Confidence interval

When an interval estimate is accompanied by a specific level of confidence (or probability), it’s called a confidence interval. It’s an estimated range that the parson’s true score will be found. The confidence interval has a score range within which a true score is likely to be found and it also consists of level of confidence that is generally between 50 and 95 (Salvia and Ysseldyke 2009)

Independent  and Dependent variables

The independent variable sometimes called the factor or treatment factor is one of the variables under study that is being controlled at or near some target value, or level, during a given experiment. The level is being changed in some systematic way from run to run in order to determine what effect it has on the responses (Lawson, 2010).

The dependent variable (or the response usually denoted by Y) is the characteristic of the experimental unit that is measured after each experiment or run. The magnitude of the response depends upon the setting of the independent variables or factors and the lurking variables (Lawson, 2010).

Slope of a standard curve represent

The slope gives information about the rate of change i.e.

Slope = m = change in y   =  ∆y /∆x

                    Change in x

The letter m is universally used in mathematics to notate slope, and the delta symbol ∆, is used to notate change. The slope-intercept form of a linear equation is y = mx + b where m is the slope and b is the y-intercept. A standard curve is a graph that is typically used to help determine the concentration of some substance (Helms, 2009).

References

American sociological association (APA) manuscript format. Courtesy of the No′eau center for writing, math and academic success. University of Hawai′i west o′ahu, 2009.

Black,K.,2012. Business Statistics: For Contemporary Decision Making. 7^th edition pages 62 and 75

Calmorin.P.L, Calmorin.A.M., 2007. Research methods and thesis writing. Second edition. ISBN 978-971-23-4927-0

Emerson L.,2005. Writing guidelines for social science students. Second edition. Pages 55 to 59

Gravetter.F.J , Wallnau.B.L., 2011. Essentials of statistics for the behavioral sciences. Seventh edition.pages 186 and 95.

Helms.R.J., 2009. Mathematics for medical and clinical laboratory professionals. Page 62

Jackson L.S., 2009. Research methods and statistics: A critical thinking approach page 352. Third edition ISBN 10: 0.499-51001-7

Knisely.K. 2005.a student handbook for writing in biology second edition. Page 32.  ISBN 978-0-7167-6709-1.

Lawson.J., 2010.design and analysis of experiments with examples of SAS. ISBN 978-1-4200-6060-7. Published by CRC press. Pages 3 and 4.

O′day D., Budniak. A., 2012. How to succed at university. Canadian edition

Petrie.A, Sabin.C., 2009. Medical statistics at a glance. Third edition page 24.

Salvia .J, Ysseldyke J.E, Bolt.S., 2009. Assessment: In special and inclusive education, 11^th edition. Page 62

Schwartz.B, Landrum.R.E, Gurung.R.R., 2012. An easy guide to APA style. Pages 172, 173,179, 183 and 184

Sheskin.D.,2003. Handbook of parametric and non parametric statistical procedures. Third edition, Page 156.

United Nations publication 2003, African water Journal page 96.ISBN 92-1-125089-7

Viswanathan.M., 2005. Measurement error and research design. Sage publishers

Zobel,.J., 2004). Writing for computer science. Second edition, page 30. ISBN 1852338024.