QUESTION 1 (3 marks)
a) Locate, and give the reference for, one article that represents the highest evidence available relating to the changing of intravenous administration sets.
b) According to the JBI evidence hierarchy (effectiveness domain), what level of evidence is this article?
c) What is the evidence regarding the frequency of administration set changes?
QUESTION 2 (10 marks)
a) Identify the appropriate measurement scale for the following:
Variable Measurement Scale
Time of day (Night, Dawn, Noon, Afternoon, Evening)
Ranking of journals in a category according to impact factor
Presence or absence of infection
b) You construct a survey and create categories for age – what scale is this? Identify one advantage and one disadvantage of measuring the variable in this way.
QUESTION 3 (2 marks)
The lifespan of light bulbs is normally distributed, with a mean life of 850 hours, and a standard deviation of 20 hours.
a) What would be the expected lifespan of approximately 99% of the light bulbs?
b) What percentage of light bulbs should last for at least 830 hours?
QUESTION 4 (8 marks)
Nursing staff in a surgical ward are interested in acupressure in treating postoperative nausea and vomiting. They decide to carry out a study comparing its effectiveness with that of standard treatment. Patients must consent to the study to be included.
a) Explain the difference between internal and external validity in studies such as this [2 marks]
b) Identify 3 threats to internal validity in this study and suggest strategies by which they could be prevented or reduced [6 marks]
QUESTION 5 (6 marks)
A class of 30 students received the following marks (expressed as percentages) for their overall assessment.
Student Mark Student Mark Student Mark
Grace 50 Sunil 62 Ahmed 67
Jianxia 76 Louisa 90 Tracey 72
Mark 82 David 72 Lian 62
Herlina 52 Jennifer 54 Abdul 20
James 64 Matilda 69 Melanie 65
Bianca 77 Elise 43 James 59
Mishal 35 Ramon 75 Jehan 67
Nawal 85 Caroline 62 Diana 58
Chris 78 Zara 70 Peter 68
Simon 60 Sunit 56 Rebecca 53
a) Calculate: [3 marks]
i) The mean
ii) The median
iii) The mode
b) You wish to know whether there is a difference between the marks obtained by male and female students. How would you examine the association between these two variables? [1 mark]
c) What statistical test would you perform to examine the significance of this association? [1 mark]
d) You are also interested to know whether there is an association between the marks obtained for this subject, and those obtained for another unit which all of the students have taken. To compare the marks you calculate Pearson’s correlation coefficient, and obtain a result of -0.334. What can you conclude about the relationship between the two sets of marks? [1 mark]