Class notes
Epid 2200 tutorial 8
- Course
- Institution
Epid 2200 tutorial 8 with question and answer
[Show more]
Seller
Follow
kyuju
Content preview
Q1James Lind in 1747 carried out a trial comparing treatments for scurvy, now known to be
a consequence of vitamin C deficiency. Provide one strength and one weakness of either
the trial design or analysis using the description provided by Gordis (page 198):
“I took 12 patients in the scurvy on board the Salisbury at sea. The cases were as similar
as I could have them...they lay together in one place and had one diet common to them
all. Two of these were ordered a quart of cider per day...Two others took 25 gutts of elixir
vitriol...Two others took two spoonfuls of vinegar...Two were put under a course of sea
water...Two others had two oranges and one lemon given them each day...Two others
took the bigness of nutmeg. The most sudden and visible good effects were perceived
from the use of oranges and lemons, one of those who had taken them being at the end
of 6 days fit for duty...The other...was appointed nurse to the rest of the sick.”
Strength) Designed experiment, tried to select subjects with similar levels of illness, common
diet
Weakness) Not randomized, no rationale for sample size,No formal statistical analysis, probably
not an issue assuming there were no prior patients who spontaneously improved
Q2
Which of the following are not suitable scarification variables for random assignments
1. Age
2. Hospital where treated
3. Patient compliance with assi\ged intervention
4. All of the above
5. None of the above
C. Since can only be known following random assignments. Variables used for stratified random
assignment must be identified immediately prior to random assignment
Q3
To be internally valid, the people enrolled in a trial must be representative fo the general
population
Comment…
A sample of clinical trial subjects representative of people in the population with the disease
being studied ensures external validity buy tells us noting about internal validity. Consider a
clinical trial comparing treatments for women newly diagnosed with cervical cancer. Ideally one
would enroll a random sample of such women enhancing external validity. In practice subjects
who participate in randomized trials are never a random sample as not all eligible subjects will
provide informed consent and so cannot be randomized
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller kyuju. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $5.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
62890 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now