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sing a computer-based list of registered students, 200 freshmen, 200 sopho- ors

ID: 3199151 • Letter: S

Question

sing a computer-based list of registered students, 200 freshmen, 200 sopho- ors and 200 seniors were selected at random from each of these four 3. (5 points) U mores, 200 juni classes. What kind of sampling design was employed? 4. (15 points) Researchers wanted to evaluate whether ginko, an over-the-counter herb marketed as enhancing memory, improves memory in elderly adults as measured by objective tests. To do this, they recruited 200 people older than 60 years of age and in good health. Participants were randomly assigned to receive day, or a matching placebo. The measure of memory improvement after 6 weeks was determined by a standardized test of learning and memory (a) (2 points) What type of experimental design was this? ginko, 40mg 3 times per (b) (2 points) What is the population being studied? (c) (2 points) What is the response variable in this study? (d) (2 points) What is the factor? (e) (2 points) What are the treatments? (f) (5 points) Draw a diagram experiment outlining the experiment (your diagram should have the same structure as the ones done in class or in the book).

Explanation / Answer

Answers

Q3

The population of registered students is divided into 4 groups (strata) and from each group a random sample is taken to make a composite sample to derive information about the population. Thus, it is a case of Stratified Random Sampling ANSWER

Q4a

Experimental units (200 recruited people) are randomly but equally divided into two groups – each group receiving one treatment.

Thus. it is a case of Completely Randomised Design (CRD) ANSWER

Q4b

Population of elderly adults (over 60 years of age) ANSWER

Q4c

Measure of memory improvement as determined by a standard test of learning and memory ANSWER

Q4d

Factor: Memory improvement ANSWER

Q4e

Treatments: Ginko, an over-the-counter herb claimed to improve memory and Placebo – first acting as treatment and the second acting as control. ANSWER

DONE