Chapter 2. The Process of Science II

Introduction

Objectives

Each class will complete an experiment designed to quantitatively answer a specific question.

Part 1. Data Collection

In lab this week we will be focusing on an experiment comparing each student’s reaction time to a given visual stimulus and given auditory stimulus. We will then compare reaction time from the visual stimulus to the same stimulus while the student is given a spelling task.

We will collect data in lab for each student using the iWorx system of data collection. Each student will fill in the data table as part of the Hand-In.

Your TA will explain our method of collecting data. We will be seeking to answer these questions. Note that the questions are quite specific.

Question 1: Is my reaction time faster to an auditory stimulus than to a visual stimulus?

NULL HYPOTHESIS 1

Alternative hypothesis 1

Question 2: Is my reaction time different to a visual stimulus if I am working on a mental puzzle?

NULL HYPOTHESIS 2

Alternative hypothesis 2

While your fellow students are collecting data, you can be completing parts of the Hand-In at the end of this chapter.

Part 2. Data Organization

It is very important to keep accurate records from your experiment. Organizing tables for your data before you begin can be a very useful habit. Think through all of your variables and create a table that makes room for all of them.

For this lab and as an example, we have provided a data table. You should include headings for all variable and a descriptive title. There should be enough information that if you look at it a week from now, you would know exactly what you did.

As part of your Hand-In, you will calculate mean and standard deviation for each column of data. Standard deviation can be calculated using an Excel spreadsheet.

For our purposes, we will recognize that two means are different if the difference between the means is greater than one standard deviation. That is, you can call one value greater than the other if the difference is greater than the standard deviation of one.

USING SPREADSHEETS TO CALCULATE MEANS AND STANDARD DEVIATION

Steps to calculate mean and standard deviation.

Enter your data into an Excel sheet. Include as many significant figures as you have.

The mean or average is a common measure of central tendency.

To calculate the mean or the average: In the cell where you want to have the average, type “=average” (and then highlight the cells you want to average).

The standard deviation is a measure of how much variability there is around the mean. A small number means that there is very little variation, and a large number means there is a lot of variability around the mean.

To calculate the standard deviation, in the cell where you want the standard deviation, type “=STDEV” (and then highlight the cells you want to calculate standard deviation).

WRITING SCIENTIFIC PAPERS AND LAB REPORTS

Modified from:

TITLE PAGE

The title page should include the title (a brief and original but descriptive title for the study that was done), the authors’ names, and any other information required by the journal (or instructor). For our lab reports include your name, your TA’s name, your section number, and the date. The title page should be a separate page.

ABSTRACT

The abstract is a brief summary of the main sections of the paper. The abstract allows readers to identify the basic content of the paper, determine its relevance to their interests, and decide whether they will read the paper. The abstract should state the principal objectives and scope of the investigation, describe the methodology, summarize the results, and state the principal conclusions. The abstract should be written in past tense (the work is already done). No references or citations should be put into the abstract and nothing should be in the abstract that is not in the paper. Many journals will limit the length of the abstract to about 15% of the paper length. Although the abstract comes first in a paper, it should be written last, as it incorporates information that you have put into the paper.

INTRODUCTION

The purpose of the introduction is to supply background information so that a reader can understand the reasoning behind the study and evaluate the rationale for it without having to refer to previous publications. Citations that are used should provide the most important background information and not superfluous facts. In a good paper, the introduction will include the nature and scope of the problem, a review of literature to orient the reader, a brief statement of the method of the investigation, the principal results, and the principal conclusions. The nature and scope of the problem should include the question that is being asked and the hypothesis being tested. Any information that is not original thought or your hypothesis, that comes from other people’s writings or literature, needs to be cited. This means that in the paper, you must give credit where credit is due. Citations should be in parenthetical form at the end of the sentence where you have used this type of information.

MATERIALS AND METHODS

This section gives the full details of the methods used to do the study or experiment. The main purpose of this section is to describe the experimental design so that a future worker can repeat the experiment. Scientific results need to be reproducible, and this section provides the recipe for repeating the experiments. This section should be written in past tense. The materials and methods section is not a list of the materials that you used; it is a concise description of the experimental methods giving details of equipment used and measurements that were taken.

If the exact methods used have been previously published (i.e., in your lab book) they do not necessarily need to be given in detail, but the publication should be cited. If the methods are new and unique to your study all of the details should be given. If the methods are modified from previously published work, you should cite the work and describe how you modified them.

RESULTS

The results section should give an overall description of the experiments without repeating the materials and methods and it should also present the data. The results should be writtenin past tense. The results should be short and sweet, without verbiage. This section is often the shortest of the paper but is also the most important section. Basically, the paper will stand or fall on the basis of the results. For our laboratory reports, you should verbally describe the main trends or state the main points that your graph shows. Refer to the graphs and tables in parenthetical form at the end of the first sentence where you refer to data from them.

DISCUSSION

While in the results you state your main findings, in the discussion section you explain your results. The discussion is often the hardest section to write in a paper. The discussion is where principles, relationships, and generalizations shown by the results are presented. You discuss the results, not repeat them. Show how your results agree or disagree with previously published work. Discuss any theoretical implications and practical applications of your work. For our lab reports, you may also add changes that you would make to improve the results. State whether your results support your hypothesis and discuss the implications of this. State your conclusions as clearly as possible and don’t assume anything. The significance of your work must be presented in the discussion so that readers do not end up saying “So what?” after reading the paper. The discussion can swing back and forth between present and past tenses.

REFERENCES

This is a list of the literature that you have cited in the text. It should include only those papers and books that have been used and cited. Everything cited must be in the references. Examples for the references is as follows:

For a Book

For a Paper

For a Web Page

Author, if known. Date. Full Web Address.

Each section should be set apart from the others, in the order presented here, and be labeled as Introduction, Methods, Results, etc.