Regents Prep: Living Environment: Laboratory: Organization & Analysis

Developing a Research Plan
A procedure provides a description of how to organize a scientific experiment to test a hypothesis.    The idea for research can be refined through library investigations, including the use electronic information such as e-mail and the internet, retrievals and reviews of scientific literature, and through peer feedback obtained from review and discussion of the problem, hypothesis, and procedure for experimentation before it is conducted.

Development of a research plan involves researching background information and understanding the major concepts in the area being investigated. Recommendations for the methods used for studying the problem, methods of study, technology selection and use, choice and use of proper equipment, and appropriate safety precautions should be included in the design of the experiment.

Statistical Analysis of Results
It is important to use statistical techniques to attempt to determine whether chance alone has resulted in the data obtained in a scientific experiment.  This allows the investigator to assess correspondence between the predicted result contained in the hypothesis and actual result, and reach a conclusion as to whether this hypothesis was supported.

One technique is to obtain an average or mean value for the data obtained.     The more trials of an experiment that are conducted, the more acceptable or valid that data becomes.   A minimum of three trials should be conducted of any quantitative investigation.    The average value of this data allows for the minimizing of any wildly different results in a particular trial.

Representing the Data
The type of graph used to represent the data will depend on the kind of data collected.  Some types of graphs and techniques for the construction of these appear below.

 Pie Graphs Pie graphs are great for displaying parts of a whole.  The pie graph below displays the percentage of gases in our present day Earth atmosphere.

 Line Graphs Line graphs are used to compare different sets of related data or to "predict" data that is not directly measured.  This may involve the extrapolation by extending the graph along the slope above or below the plotted data on the graph.   Line graphs may be also used to predict data between two plotted points on the graph.   Some samples uses of these techniques are illustrated in the graph below. One could use the graph above to determine the relative rates of activity of gastric protease and intestinal protease are equal at pH 5.0.    One could also determine that the activity of intestinal protease stops at a pH of 12.

 Technique for Constructing a Line Graph 1.   Identify the variables to be plotted independent variable -- the variable manipulated by the experimenter                                  --is plotted on the x-axis (horizontal axis) dependent variable -- the factor responding to changes in                                    the independent variable                               -- is plotted on the y-axis (vertical axis) 2.   Determine the scale of the axes -- determine each axis individually -- may easily be determined by taking the largest value to be plotted      and dividing by the number of blocks and then rounding up to the      nearest convenient number -- the graph should be spread to occupy the most available space 3.   Number and label each axis indicating the appropriate units. 4.   Plot each data value on the graph with a point.   5.   Draw a line that best fits the data points.        -- do not connect data points to the origin unless there is data            to support this        -- if possible, do the graph of experimental data as a "best            fit" line for the points which have been plotted. 6.   Provide a title which clearly indicates what the graph is about. 7.   If the graph has more than one set of data, provide a key        to indicate what is represented by the different lines.

 Bar Graphs Bar graphs provide another way of organizing data.   It allows the taking of several measurements of different items and then making a comparison of them.   A histogram is similar to a bar graph, but only involves one variable which is compared.   A histogram allows the sorting of data by categories, as in the example below:

Lab Drawings
Many lab reports will involve a requirement for some type of drawing.    A drawing should convey information about the experiment that the formal writing in the report does not.    The drawing must be large enough and detailed enough to convey this additional information.

Assessing Experimental Results

The results of a scientific experiment must be presented to the public and peers (other scientists) before they can be accepted.   An assumption of science is that other individuals could arrive at the same explanation if they had access to similar evidence.   The procedure used in conducting the experiment must be stated precisely enough to allow other scientists to perform the experiment and determine whether the results obtained are repeatable.   The written report for public and peer study should describe the proposed explanation, literature reviewed, the research carried out, its result, and any suggestions for further scientific research.

Scientists use peer review to assess the results of scientific investigations and explanations proposed by other scientists. It is important the other scientists critique original research conducted by scientists in this manner.  They analyze the experimental procedures, examine the data obtained in the experiment, and identify faulty reasoning in assessing the data.  Peer review also leads to scientists pointing out any conclusions that go beyond the evidence obtained.  They also may suggest alternative explanations for the same observations.

This peer and public discussion may lead to revisions of the explanation provided by the research and lead the scientist to additional research related to the original problem being investigated.   Therefore, hypotheses are valuable, even if they turn out not to be true, because frequently they lead to further investigation.

Questioning Claims

The claims made in a scientific investigation should be questioned if the data are based on very small samples.   Claims made by individuals having bias must be questioned.   Bias means to have an opinion about the experimental results before the investigation which will lead to the  misinterpretation or manipulation of the data obtained in the experiment.    An improperly controlled scientific experiment must be questioned.   The experiment should contain at least one clear control and one independent variable.   The conclusions obtained in an experiment must be questioned if they are based on the faulty, incomplete, or misleading use of numbers.  Fact and opinion must not be intermingled in a proper scientific experiment.  The results of the experiment must cite adequate evidence and have its conclusion following logically from this evidence.

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