Research Methods (BIOL1070)
Part A : Workshop
The aim of this workshop is to give you some experience using standard statistical treatments of data using
statistical software. The package we will use for this workshop is Minitab. It is the package used as the
standard statistical software by the Mathematics and Statistics courses at RMIT and Chemistry also has a site
licence for it Most of the analyses in this workshop can be done using Excel but Excel is not very user-
friendly for statistical analyses. The analyses in Minitab can be done from simple pull-dovm menus and there
is a good on-line help facility. You can copy-and-paste data from Excel into Minitab. For the assessment you
should enter your results into the attached pro forma.
Case Study 1
Analyst A Analyst B
The above results were obtained by two analysts using a new method for determination of Nickel in a
standard reference alloy containing a certified value of 4.49% Ni
For this data we want to determine the standard statistics:- (i) mean (ii) variance (iii) standard deviation and
(iv) conﬁdence intervals for the mean. This data enables us to answer the following questions:-
(a) Which analysis is the most accurate? (i.e. closest to the certiﬁed value)
(b) Which analysis is the most precise? (i.e. which has the smallest spread, or variability, of values
As well we can use the t-test to answer the following:«
(c) Is there any evidence, with either analyst, of a systematic error? I.e. does either average differ
signiﬁcantly from the certiﬁed value?
(d) Do the results of each analyst differ signiﬁcantly?
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