reading

Appendix 6: Using Software to Draw Tables, Graphs and Calculating Descriptive Statistics

Wiley-Blackwell is an imprint of John Wiley & Sons, formed by the merger of Wiley's global Scientific, Technical and Medical business with Blackwell Publishing.

Registered office: John Wiley & Sons, Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK

For details of our global editorial offices, for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at www.wiley.com/wiley-blackwell

The right of the author to be identified as the author of this work has been asserted in accordance with the UK Copyright, Designs and Patents Act 1988.

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by the UK Copyright, Designs and Patents Act 1988, without the prior permission of the publisher.

Designations used by companies to distinguish their products are often claimed as trademarks. All brand names and product names used in this book are trade names, service marks, trademarks or registered trademarks of their respective owners. The publisher is not associated with any product or vendor mentioned in this book. This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold on the understanding that the publisher is not engaged in rendering professional services. If professional advice or other expert assistance is required, the services of a competent professional should be sought.

The contents of this work are intended to further general scientific research, understanding, and discussion only and are not intended and should not be relied upon as recommending or promoting a specific method, diagnosis, or treatment by physicians for any particular patient. The publisher and the author make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation any implied warranties of fitness for a particular purpose. In view of ongoing research, equipment modifications, changes in governmental regulations, and the constant flow of information relating to the use of medicines, equipment, and devices, the reader is urged to review and evaluate the information provided in the package insert or instructions for each medicine, equipment, or device for, among other things, any changes in the instructions or indication of usage and for added warnings and precautions. Readers should consult with a specialist where appropriate. The fact that an organization or Website is referred to in this work as a citation and/or a potential source of further information does not mean that the author or the publisher endorses the information the organization or Website may provide or recommendations it may make. Further, readers should be aware that Internet Websites listed in this work may have changed or disappeared between when this work was written and when it is read. No warranty may be created or extended by any promotional statements for this work. Neither the publisher nor the author shall be liable for any damages arising herefrom.

Essential laboratory skills for biosciences / Mohammed Meah and Elizabeth Kebede-Weshead.

1. Chemistry–Laboratory manuals. 2. Chemical apparatus–Handbooks, manuals, etc.

Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books.

Chapter 1 Measurements and Calculations

Figure 1.1 Accuracy and precision shown on a target

Figure 1.2a Beaker

Figure 1.2b Conical (Erlenmeyer) flask

Figure 1.2c Measuring cylinder

Figure 1.2d Burette

Figure 1.2e Volumetric flask

Figure 1.2f Pipette

Figure 1.3 Location of the meniscus of a liquid

Figure 1.4 Parts of a Gilson pipette

Figure 1.5 Circle of pipettes

Figure 1.6 Tips used with pipettes

Figure 1.7 Setting the volume on a Gilson pipette

Figure 1.8 Types of pipette tips

Figure 1.9 Pipette inserted into beaker

Figure 1.10 Ejecting tip using tip ejector button

Figure 1.11 Multichannel pipette

Figure 1.12 Pasteur pipette

Figure 1.13 Portable digital top-loading balance

Figure 1.14 Plastic boat

Figure 1.15 Spatula

Figure 1.16 A typical analytical balance

Chapter 2 Preparing Solutions

Figure 2.1 Wash bottle

Figure 2.2 Serial dilution of a stock solution

Chapter 3 Separation of Liquids and Solids

Figure 3.1a Funnel

Figure 3.1b Cone-shaped filter paper

Figure 3.1c Fluted-shaped filter paper

Figure 3.2 Buchner funnel

Figure 3.3 Side-arm filtering flask

Figure 3.4a Low-speed centrifuge

Figure 3.4b High-speed centrifuge

Figure 3.5 Microhaematocrit centrifuge

Figure 3.6a Capillary tube

Figure 3.6b Capillary tube showing separated components after centrifugation

Figure 3.7 Chromatogram showing baseline, spots and solvent front

Figure 3.8 Gel electrophoresis chamber

Figure 3.9 Gel electrophoresis wells

Chapter 4 Common Techniques and Equipment

Figure 4.1 pH paper

Figure 4.2 pH meter

Figure 4.3 Spectrophotometer

Figure 4.4 Cuvettes

Figure 4.5 Standard curve of light absorption against concentration

Figure 4.6 Inoculating loop

Figure 4.7 Bunsen burner

Figure 4.8 Petri dish

Figure 4.9a Streak plate

Figure 4.9b Plate with colonies

Chapter 5 Microscopy and Histology

Figure 5.1 Binocular light microscope

Figure 5.2a Objective lens of microscope

Figure 5.2b Ocular lens of microscope (eyepieces)

Figure 5.2c Stage and clips to hold slide

Figure 5.3 Adjustment of ocular lens

Figure 5.4 Ocular micrometer

Figure 5.5 Stage micrometer

Figure 5.6 Overlaying of ocular and stage micrometers

Figure 5.7 Unstained slide with wax covered section

Figure 5.8a H & E staining tray

Figure 5.8b Placing slide in Erlich's haematoxylin

Figure 5.8c Making a permanent mount of stained tissue

Figure 5.8d Permanent slide (stained)

Figure 5.9 Haemocytometer

Figure 5.10 Haemocytometer grid with dimensions

Chapter 6 Cardiorespiratory Measurements

Figure 6.1a Sphygmomanometer

Figure 6.1b Sphygmomanometer and stethoscope

Figure 6.2 Automatic blood pressure monitor

Figure 6.3 Finger prick pen

Figure 6.4a Lancet

Figure 6.4b Pushing lancet into pen

Figure 6.4c Removing base of lancet

Figure 6.4d Pen containing inserted lancet

Figure 6.4e Pen placed perpendicular to side of finger

Figure 6.4f Ejection of used lancet from pen

Figure 6.5 Wet seal spirometer

Figure 6.6a Controls of wet seal spirometer

Figure 6.6b Controls to switch between spirometer and atmosphere

Figure 6.7 Loading vitalograph chart paper onto moveable tray

Figure 6.8a Vitalograph at the beginning of a blow

Figure 6.8b Vitalograph at the end of a blow

Figure 6.9 Electronic spirometer (MicroPlus)

Chapter 7 Recording and Presenting Data

Figure 7.1 Example of line graph

Figure 7.2 Example of bar graph

Figure 7.3 Example of scatter graph

Figure 7.4 Drawing line of best fit using linear regression

Figure 7.5 Testing the line of best fit

Figure 7.6 Pie chart

Appendix 4 Principle of Spectrophotometry

Figure A4.1 Components of a spectrophotometer

Appendix 6 Using Software to Draw Tables, Graphs and Calculating Descriptive Statistics

Figure A6.1 Bar graph showing changes in the mean heart rate (±SEM) of students at rest and during a maths test

Chapter 1 Measurements and Calculations

Table 1.1 Common measurements and their units and symbols

Table 1.2 Common prefixes

Table 1.3 Common measurement units of volume

Table 1.4 Volume ranges for Gilson pipettes

Chapter 2 Preparing Solutions

Table 2.1 Standard solutions prepared from a stock solution by dilution

Chapter 4 Common Techniques and Equipment

Table 4.1 Acids and bases commonly used in the laboratory

Table 4.2 Volumes of stock and water used to produce diluted standard solutions

Table 4.3 Absorbances of the standard and unknown solutions

Chapter 7 Recording and Presenting Data

Table 7.1 Examples of independent and dependent variables

Table 7.2 Glucose tolerance test for normal and diabetic persons

Appendix 6 Using Software to Draw Tables, Graphs and Calculating Descriptive Statistics

Table A6.1 Example of a table using Microsoft Word or Excel

Table A6.2 Descriptive statistics

We are extremely grateful to Varoopah Senthuran for taking the majority of photographs, and her enthusiasm, support and assistance in a variety of other tasks during the production of this book. Discussions on book contents with John Allum and Alberto Sanchez-Medina at the initial stage of writing the book were highly appreciated by the authors. We are also grateful to Stefano Casalotti and Winston Morgan for their suggestions and helpful feedback on the manuscript. We would also like to thank the following, for their help in providing the various apparatus in different laboratories, and for suggestions in taking better photographs: Susan Harrison, Raymond Stoker, Stephen Garrad, Duncan Kenedy, Kevin Clough, Manchu Ambihaiphan, Ashford Clovis, and Keith Eley.

We would also like to thank the publishing editors of Wiley Publishers for their patience, understanding and guidance in the preparation of this book.

‘Biosciences’ is a broad term covering a wide range of subjects, including biology, biochemistry, biomedical science, biotechnology, forensic science, microbiology, physiology, pharmacology, and toxicology. Studying the biosciences involves a large amount of practical work in laboratories. These sessions involve following instructions from the lab instructor, following a practical schedule, learning techniques, taking measurements, observing and recording data, calculating and presenting data.

You will find that in performing practical laboratory tasks, techniques are often repeated (e.g. pipetting volumes, preparing solutions or producing calibration curves). You will be required to apply these fundamental skills across the bioscience subject areas.

This book is intended to act as a laboratory guide to help you to complete these practical tasks successfully by focusing on:

The book is intended for those who are new to, or have little experience of the laboratory techniques and equipment used in studying biosciences. It may also be useful to those who need to refresh some of their knowledge of laboratory skills, or those doing projects at both undergraduate and postgraduate levels. This book emphasizes ‘essential’ skills and the practical steps required to use equipment and learn techniques. The authors assume that the reader has very little prior knowledge of techniques in the biosciences. To make the process easier, we have emphasized the step-by-step approach in the practical procedures, together with a wide range of photographs of equipment and accessories.

This is not intended to be a comprehensive text book, so you will find that the background theory to the techniques (Chapters 3, 4, 5 and 6) is brief. Also, some techniques in the various bioscience fields, and some particularly advanced techniques that you may be using in years two and three of your degree may not have been included. Please note that the steps shown for procedures are not universal, and you will come across some differences in practice, depending on the technique and equipment you are using.

Chapter 1 covers the fundamental basis of measurements and units, and common mathematical calculations you may come across. You must understand terms which are commonly used, such as ‘moles’, ‘molarity’ and ‘dilutions’. In addition, you must be able to convert between common prefixes or powers of ten. You will have to practise doing calculations involving moles, molarity and powers. Pictures of glassware commonly used in the lab are included.

Chapter 2 gives details of common terms associated with solutions and how different types of solutions are prepared.

Chapter 3 contains details of techniques used to separate liquids and solids, such as filtration, centrifugation, chromatography and gel electrophoresis. Some of the chromatography methods using expensive equipment will not be routinely used in undergraduate bioscience practicals, especially at entry level. Therefore, instead of detailed procedures of the methods, we give the basic principles and an outline of the methods. It is intended to help distinguish the methods which may appear confusing for a beginner.

Chapter 4 contains details of a wider variety of techniques and equipment, including spectrophotometry, pH meters, titration and aseptic techniques.

Chapter 6 covers a range of techniques, investigating cardiopulmonary function in humans.

Chapter 7, the final chapter, describes how to record and present your data, with examples of typical tables and graphs.

Appendices in bold face to highlight the section give more details of laws of powers and logarithms, more theory on some techniques (e.g. spectrophotometry), and the use of common software such as Microsoft Word and Excel to produce tables, graphs and descriptive statistics. There is only a brief description of statistical analysis (descriptive statistics), so you will need to refer to statistical texts to investigate differences in mean data (inferential statistics).

We hope this book will be a useful ‘companion’ to the lab schedule and lecturers' instructions, and will help to make the student more independent in the laboratory.

Before performing any laboratory work, it is essential that health and safety considerations are followed with regard to hazards and risk to you and others. Make sure you follow the basic important rules in a laboratory as shown below.