Re: Curious about K-S test in NPTESTS

Posted by Jon Peck on Dec 08, 2018; 10:28pm
URL: http://spssx-discussion.165.s1.nabble.com/Curious-about-K-S-test-in-NPTESTS-tp5737122p5737123.html

If you duplicate the data, so that you have 20 records, the sig level goes from .367 to .068.  Triple it and the sig is .013.

Even using Exact Tests (on the original data), the K-S test sig level is .146.  Even the Mann-Whitney test does not detect the difference.

So you need more data.

On Sat, Dec 8, 2018 at 2:22 PM Beckstead, Jason <[hidden email]> wrote:

Hi all,

I am working to compare various sample distributions and thought that the Kolmogorov-Smirnov test in NPTESTS would be appropriate. However, it doesn’t reveal these two obviously different distributions as significant. Syntax is below. Any insight would be appreciated.

Jason

 

DATA LIST FREE/FORM X FREQ.

BEGIN DATA.

1 1  7

1 2 24

1 3 38

1 4 24

1 5  7

2 1 20

2 2 20

2 3 20

2 4 20

2 5 20

END DATA.

WEIGHT BY FREQ.

VARIABLE LEVEL X (SCALE).

*Nonparametric Tests: Independent Samples.

NPTESTS

  /INDEPENDENT TEST (X) GROUP (FORM) KOLMOGOROV_SMIRNOV

  /MISSING SCOPE=ANALYSIS USERMISSING=EXCLUDE

  /CRITERIA ALPHA=0.05  CILEVEL=95.

 

_____________________________________________________________

 Jason W. Beckstead, Ph.D.       

  Associate Professor/Quantitative Methodologist

  University of South Florida College of Public Health

  13201 Bruce B. Downs Blvd., MDC56, Tampa, FL 33612, USA

  Statistical Editor, International Journal of Nursing Studies

  phone: [phone]  fax: [phone]          

  personal website:  http://personal.health.usf.edu/jbeckste/

  International Journal of Nursing Studies  http://www.elsevier.com/ijns

 

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