DATA RECORDING - COMPUTER METHODS
Computerisation:
The final phase in data assembly is
computerisation. Important aspects of this phase
are
- Enter and verify
- Validation
- range checks, eg a lamb liveweight of 101 kg
- value checks, eg if there are three treatments
coded 1, 2, 3, a value of 4 is incorrect,
- concordance checks repeated measures
- Data may be entered to a data base which can
carry out many of these checks.
- Security
- Screening precedes analysis
Electronic recording
Excel for recording and preliminary
data viewing
An introduction to the use of Microsoft Excel
Introductory
- Getting into Excel
- Some basic concepts
- How to open and save a worksheet
- How to move around a worksheet
- How to select cells
- How to enter data
- How to edit data.
- How to format numeric data and text
- How to use formulae i.e. calculate totals, means,
etc.
More advanced topics
-Tagging notes onto cells
-Protecting cells
-Repeating numbers and entering a series of
numbers
-Searching and Replacing
-Sorting Data
-Formulae and functions
-Copying data to and from SAS
-Charts and presentation of results
Managing an Excel data recording file.
Managing an Excel data recording file.
Always keep a copy of essential data files on a
floppy disk to avoid tears if the hard disc
crashes.
Preliminary information
Title, including year
List of data in the file
List of analyses in the file
List of units used for each variable recorded and
derived
Definition of treatments and factor levels
Information with data
Notes to indicate changes and reasons for changes
Dates of recording, where relevant
Use colour coding of text, data and cell
backgrounds as well as font size and characteristics
(e.g. bold, italic) to lead the eye through the
worksheet
Layout of data
In general, enter the data so that each experimental
unit is recorded across the cells in a single row, with
variables (e.g. green weight, dry matter content
etc.) occupying columns.
Reserve the first few columns for information
describing the experimental units and their
structure, such as Tag number, Treatment
number/factor level(s), replicate number etc. The
window can then be split into two panes vertically
and any data columns examined in the right hand
pane with the structural information also in view in
the left hand pane.
Arrange the data lines without a break.
Summaries and diagostics
Missing data and empty cells
Exercise and example.
Import to SAS
Exercise: Enter the data for example 1 of the
exercise sheet. Save the file as EXAMPLE1.XLS.
More advanced topics
Tagging notes onto cells
Insert - Comment.
Editing comments
Protection - you can protect cells, sheets or
workbooks to prevent the data from been
overwritten by accident.
Format - Cell Protection
Tools Protection - Protect sheet
Tools - Protection - Unprotect sheet.
Repeating numbers - Entering a series of
numbers
Searching and Replacing.
Edit - Find
Edit - Replace
Sorting Data.
Select the cells you want to sort. NB only those
cells will be sorted, not all the data. Sorting with
formulae.
Data - Sort
Formulae and functions
Simple Formulae
Mean, Max, Min, Count, Stdev
Reference cells
Checking Data Entry.
IF functions
For example if you knew response times (C2) were
within the range 900 - 1500, use
=IF(AND(C2>900, C2<1500),"","Value is out of
range")
which results in a warning when the value entered
is not between 900 and 1500. Other Logical
functions include OR, NOT.
Copying data from SAS
Data – text to columns
Copying data to SAS
File import data (spreadsheet closed).
Charts
In worksheet or as a chart
Labelling
Dynamic editing of a chart
Sizing and transferring to Word - links
Customising Excel and add-ins
Tools customise – Drawing (allows text box
insertion)
Tools – add ins – data analysis
Adding in a SED or LSD indicator to a chart