How to calculate the power of a study ? - USMLE Forums
USMLE Forums Logo
USMLE Forums         Your Reliable USMLE Online Community     Members     Posts
Home
USMLE Articles
USMLE News
USMLE Polls
USMLE Books
USMLE Apps
Go Back   USMLE Forums > USMLE Step 1 Forum

USMLE Step 1 Forum USMLE Step 1 Discussion Forum: Let's talk about anything related to USMLE Step 1 exam


Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 12-11-2010
USMLE Forums Addict
 
Steps History: 1 + CS
Posts: 103
Threads: 29
Thanked 18 Times in 13 Posts
Reputation: 28
Stats How to calculate the power of a study ?

hey ppl plzzz help me out with this ......how to determine the power of a study ? ....how to calculate it?....i cant figure it out :O pllzzzzz helpppp!!!
Reply With Quote Quick reply to this message



  #2  
Old 12-11-2010
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 742
Threads: 137
Thanked 2,428 Times in 441 Posts
Reputation: 2531
Default 1 - type II error

The power of a statistical test is the probability that the test will reject a false null hypothesis (i.e. that it will not make a Type II error). As power increases, the chances of a Type II error decrease. The probability of a Type II error is referred to as the false negative rate (β). Therefore power is equal to 1 − β, which is equal to sensitivity.
Reply With Quote Quick reply to this message
The above post was thanked by:
Carolina_USMLE (12-18-2014)
  #3  
Old 12-11-2010
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 742
Threads: 137
Thanked 2,428 Times in 441 Posts
Reputation: 2531
Default Don't confuse it with accuracy

The accuracy of the study is different.

It's calculated by the following formula:

Accuracy = TP + TN / TP + FP + TN + FN
Reply With Quote Quick reply to this message
  #4  
Old 12-11-2010
USMLE Forums Addict
 
Steps History: 1 + CS
Posts: 103
Threads: 29
Thanked 18 Times in 13 Posts
Reputation: 28
Default

thxxxx sooo much for ur reply rasheed .....n plzzz can u explain it with an example
Reply With Quote Quick reply to this message
  #5  
Old 08-25-2011
bebix's Avatar
USMLE Forums Master
 
Steps History: 1+CK+CS+3
Posts: 1,357
Threads: 194
Thanked 3,259 Times in 881 Posts
Reputation: 3269
Default

Quote:
Originally Posted by rasheed View Post
The power of a statistical test is the probability that the test will reject a false null hypothesis (i.e. that it will not make a Type II error). As power increases, the chances of a Type II error decrease. The probability of a Type II error is referred to as the false negative rate (β). Therefore power is equal to 1 − β, which is equal to sensitivity.
Therefore power is equal to 1 − β, which is equal to sensitivity??
Reply With Quote Quick reply to this message



Reply

Tags
Biostatistics-Epidemiology

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the USMLE Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Medical School
Choose "---" if you don't want to tell. AMG for US & Canadian medical schools. IMG for all other medical schools.
USMLE Steps History
What steps finished! Example: 1+CK+CS+3 = Passed Step 1, Step 2 CK, Step 2 CS, and Step 3.

Choose "---" if you don't want to tell.

Favorite USMLE Books
What USMLE books you really think are useful. Leave blank if you don't want to tell.
Location
Where you live. Leave blank if you don't want to tell.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes


RSS Feed
Find Us on Facebook
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

USMLE® & other trade marks belong to their respective owners, read full disclaimer
USMLE Forums created under Creative Commons 3.0 License. (2009-2014)