General Instructions
These questions require you to select and run appropriate statistical tests using SPSS and to write a fully detailed commentary explaining all of your reasoning and rationale. You must include all appropriate information from the SPSS Output file for each question and EMBED the output WITHIN the commentary at the appropriate place. The written commentary must:
· be word-processed
· only cover the points specified in the questions
For each question detail what statistical test(s) were run, showing all relevant output generated and explain why this test(s) is appropriate? Marks will be awarded for (i) selection of co
ect procedures including those needed to verify test assumptions (ii) co
ect data entry and execution of tests (iii) overall presentation of the answer so that it contains only relevant material, in a logical order, neatly set out, without repetition.
For the commentary, marks will be awarded for (i) general presentation and use of English (ii) grasp of statistical theory and concepts (iii) understanding of the SPSS Output.
Mark allocation is as follows: Q1 20%; Q2 25%; Q3 25%; Q4 30%.
Q1
It is thought that a new drug A might lead to a reduction in diastolic blood pressure. An experiment was performed using 20 male volunteers, 10 of whom were randomly selected to take a pill containing drug A and 10 who were randomly chosen to take a pill which contained placebo. Diastolic blood pressure was measured for the 2 cohorts following treatment. The values obtained for the diastolic blood pressure (mmHg) is shown below.
Placebo XXXXXXXXXXDrug A
90 71
95 79
67 69
120 98
89 91
92 85
100 89
82 75
79 78
85 80
What can be deduced by statistical analysis about the effect of drug A on the diastolic blood pressure observed in this study?
20 marks
Q2
A research laboratory is testing the effect of 5 different drug candidates on the concentration of nitric oxide (NO) in rat plasma to determine whether there is any difference observed for the different drugs. Dataset Q2_Autumn20.xls contains the concentration of NO, in mmol/L for an equal number of rats, obtained by random sampling, following treatment with the 5 different drugs. Using statistical analysis determine if the treatments result in a significant change to the concentration of NO in rat plasma and if so, where those differences lie.Â
25 marks
Q3
A retrospective analysis was performed on 933 patients with clinically localised prostate cancer who underwent radical prostatectomy between March 1999 and July 2009. Some characteristics of the patients were recorded, and the patients were split into those with a low socioeconomic status (SES) who were treated in the public health system, and those with a high socioeconomic status who were treated in a private hospital.
Low SES (n=379)
High SES (n=554)
Total (n=933)
Age (years)
<65
145
290
435
65 and olde
234
264
498
Serum PSA (ng/mL)
<10
244
342
586
10-20
100
163
263
>20
35
49
84
Pathological stage
T2
272
415
687
T3
107
139
246
Tumour Grade / Gleason Score
<7
193
344
537
7 or more
186
210
396
Using statistical analysis investigate whether there is evidence that the socioeconomic status of the patient, is related to their age, serum Prostate Specific Antigen (PSA) level, Pathological stage or Tumour grade of the patient.
Discuss your results and any significant association found. For any significant association explain the nature of the association.
25 marks
Q4
A study was conducted to investigate whether the final exam result gained for a group of 25 Biomedical Science students was in any way dependent upon the results that the students had obtained in previous assessments. These being:
· An in-class Test
· A Coursework assignment
· A Mock Exam
The file Q4_Autumn20.xls details the marks obtained for the students final exam as well as their previous assessments.
Using the data contained within this file, determine by statistical analysis which variables have an impact on the final exam mark, and the extent of the relationship.
30 marks