Good example Homework Assignment 4

 

Article:

Testing: with decaf, lose the jitters, but gain the gunk?

Nov 29th, 2005

Source: msnbc health: New York Times

NOTE: you cannot use this article for the homework assignment

 

I.                   Goal: To determine whether drinking decaffeinated coffee increases (bad) cholesterol levels

II.                Model being tested:

Model 1: Decaf coffee increases cholesterol levels

Model 2: Decaf coffee does not increase cholesterol levels

III.              Design Features:

1. Experiment:

a) what done: participants were assigned to drink different amounts of decaf coffee or no coffee

b) for what purpose: to determine the effects of decaf on cholesterol levels

(you can answer this all in 1 simple sentence, just address both parts a and b)

                       2. Controls:

a)      Factors controlled for:  all except decaf coffee (because subjects were randomly assigned to groups - NOTE THAT ALL NON-TREATMENT FACTORS ARE CONTROLLED ONLY WHEN THERE IS RANDOM ASSIGNMENT TO TREATMENT AND CONTROL GROUPS, SO DON'T JUST CUT AND PASTE THIS LINE INTO YOUR ASSIGNMENT WITHOUT CHECKING INTO THIS AND THINKING ABOUT IT!

b)      Control group = people who drank no coffee

c)      Treatment group = people who drank decaf coffee

 

 

  1. Explicit protocol
    1. relevant: yes
    2. status: present
    3. quotes: “volunteers assigned at random to three groups. 59 drank no coffee, 63 drank 3-6 cups of decaffeinated coffee, and 66 drank 3-6 cups of caffeinated coffee.  The coffee was prepared according to specific brewing instructions, and all subjects drank their coffee black”. 

 

  1. Replication
    1. relevant: yes
    2. status: present
    3. quotes: “187 volunteers”

 

  1. Standards
    1. relevant: yes
    2. status: present
    3. quotes: “volunteers assigned to three groups. . 59 drank no coffee, 63 drank 3-6 cups of decaffeinated coffee, and 66 drank 3-6 cups of caffeinated coffee.”

(NOTE: this is not the best example of a standard, this is simply a basis for comparison between the groups)

 

  1. Randomization
    1. relevant: yes
    2. status: present
    3. quotes: “ included 187 volunteers assigned at random to three groups.”

 

  1. Blind
    1. relevant: yes
    2. status: ambiguous
    3. quotes: article did not mention if study was administered blindly.

NOTE: If your article does not state clearly that blind was absent (if it does, provide that quote), put ambiguous and quote supporting that or explanatory statement, as above.

 

 


Second good example of Homework Assignment 4

Article:

Vitamin E fails to stop progress of Alzheimer’s

April 19th, 2005 by Nicolas Bakalar

Source: New York Times

NOTE: you cannot use this article for the homework assignment

 

IV.              Goal: To determine whether taking Vitamin E slows progression of Alzheimer’s

V.                Model being tested:

Model 1: Vitamin E slows progression of Alzheimer’s disease

Model 2: Vitamin E does not slow progression of Alzheimer’s disease

 

VI.              Design Features:

1. Experiment:

a) what done: participants were assigned to receive Vitamin E or a placebo

b) for what purpose: to determine the effects of Vitamin E on the rate of pogression of Alzheimer’s disease

(you can answer this all in 1 simple sentence, just address both parts a and b)

 

                       2. Controls:

a)      factors controlled for:  all except vitamin E (subjects were randomly assigned to groups)

b)      Control group = people who took a placebo

c)   Treatment group = people who took Vitamin E

 

 

  1. Explicit protocol
    1. relevant: yes
    2. status: present
    3. quotes: “patients were randomly assigned to groups receiving a drug Aricept, vitamin E, and placebo versions of those substances.” 

 

  1. Replication
    1. relevant: yes
    2. status: present
    3. quotes: “researchers studied 769 patients”

 

  1. Standards
    1. relevant: yes
    2. status: present

3.   quotes: “At the end of one year, significant differences appeared: 38 patients in the placebo group and 33 in the vitamin E group had Alzheimer’s, compared with only 16 in the Aricept group. But among the 214 patients who progressed to Alzheimer’s over the entire 3 year course of the study, there was no significant difference among the three test groups.”

 

  1. Randomization
    1. relevant: yes
    2. status: present
    3. quotes: “patients were randomly assigned to groups receiving..”

 

  1. Blind
    1. relevant: yes
    2. status: present
    3. quotes: “patients were randomly assigned to groups receiving a drug Aricept, vitamin E, and placebo versions of those substances.” 

 

NOTE: Placebo will be accepted as evidence that study was done blindly.