Manuals/calci/CHIDIST

CHIDIST(x,df)

• 'x' is the value for which distribution is evaluated.
• 'df' is the number of degrees of freedom.

Description

• This function gives the one_tailed probability of the chi-squared distribution.
• It is denoted by $\chi ^{2}$ distribution.
• Normally categorical data's may displayed in tables. The $\chi ^{2}$ static used to compare the observed value in each table to the value which would be the expected under the assumption.
• The conditions of $\chi ^{2}$ test is
  • The table should be 2x2 or more than 2x2
  • Each observations should not be dependent
  • All expected values should be 10 or greater. 
  • The test statistic is:

$\chi ^{2}=\sum {\frac {(Oi-Ei)^{2}}{Ei}}$

The degrees of freedom are: (r–1)(c–1)

• r = No. of rows
• c = No. of columns

Where:

• Oi-the observed value in the ith cell
• Ei- the expected value in the ith cell

Also this function will the result as Error when

1. The x & df values are non-numeric
2. The x value is negative or df value is not an integer
3. The df <1 or df>10^10
4. Here CHIDIST=P(X>x),where X is a $\chi ^{2}$ random variable.

• CHIDIST(-2,1)=Error, because x is negative.
• CHIDIST(2,-1)=Error, because df<1

Examples

CHIDIST(x,df)	x	df	RESULT
CHIDIST(18,2)	18	2	0.0001234098
CHIDIST(15,1)	15	1	0.0001075112
CHIDIST(2,1)	2	1	0.157299207050
CHIDIST(-2,1)	(-2)	1	error
CHIDIST(2,-1)	2	(-1)	error

See Also

• CHITEST

References

CHI-SQUARE Distribution