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Table 4 2.5−97.5% Percentiles for unconditional and conditional outfits and infits

From: Item fit statistics for Rasch analysis: can we trust them?

  

Outfit

 

Infit

 

n

k

uncond

cond

\(1\pm 6/\sqrt {n}\)

uncond

cond

\(1\pm 2/\sqrt {n}\)

150

10

0.60–1.33

0.67–1.55

0.51–1.49

0.78–1.10

0.84–1.17

0.84–1.16

 

15

0.65–1.33

0.70–1.46

 

0.81–1.12

0.85–1.16

 
 

20

0.69–1.34

0.72–1.43

 

0.83–1.12

0.86–1.15

 

200

10

0.64–1.27

0.70–1.46

0.56–1.42

0.80–1.07

0.86–1.15

0.86–1.14

 

15

0.69–1.27

0.73–1.39

 

0.83–1.09

0.87–1.14

 
 

20

0.71–1.28

0.75–1.36

 

0.85–1.10

0.88–1.13

 

250

10

0.65–1.21

0.73–1.40

0.62–1.38

0.81–1.06

0.88–1.13

0.87–1.13

 

15

0.71–1.24

0.75–1.34

 

0.84–1.08

0.88–1.12

 
 

20

0.74–1.24

0.77–1.32

 

0.86–1.09

0.89–1.12

 

500

10

0.71–1.11

0.80–1.26

0.73–1.27

0.84–1.03

0.91–1.09

0.91–1.09

 

15

0.77–1.15

0.82–1.25

 

0.87–1.05

0.92–1.09

 
 

20

0.79–1.16

0.83–1.22

 

0.89–1.05

0.92–1.08

 

1000

10

0.76–1.05

0.85–1.18

0.81–1.19

0.86–1.01

0.94–1.06

0.94–1.06

 

15

0.81–1.08

0.87–1.16

 

0.89–1.02

0.94–1.06

 
 

20

0.83–1.10

0.88–1.16

 

0.91–1.03

0.94–1.06

 

1500

10

0.77–1.02

0.87–1.14

0.84–1.15

0.87–1.00

0.95–1.05

0.95–1.05

 

15

0.82–1.05

0.89–1.13

 

0.90–1.01

0.95–1.05

 
 

20

0.85–1.07

0.89–1.13

 

0.92–1.02

0.95–1.05

 

2000

10

0.75–1.04

0.89–1.12

0.86–1.13

0.87–0.99

0.96–1.05

0.96–1.04

 

15

0.84–1.04

0.89–1.13

 

0.91–1.01

0.96–1.04

 
 

20

0.86–1.05

0.91–1.11

 

0.92–1.02

0.96–1.04

 

3000

10

0.81–0.99

0.91–1.10

0.89–1.11

0.88–0.99

0.96–1.04

0.96–1.04

 

15

0.85–1.02

0.92–1.09

 

0.91–1.00

0.97–1.03

 
 

20

0.87–1.03

0.92–1.09

 

0.93–1.02

0.97–1.03

 

10 000

10

0.83–0.97

0.95–1.05

0.94–1.06

0.89–0.97

0.98–1.02

0.98–1.02

 

15

0.88–0.99

0.95–1.05

 

0.92–0.99

0.98–1.02

 
 

20

0.90–1.00

0.96–1.05

 

0.94–1.00

0.98–1.02