FMPMonotonicityCheck: Utility function for checking FMP monotonicity

In FMP: Filtered Monotonic Polynomial IRT Models

Description

Utility function for checking whether candidate FMP coefficients yield a monotonically increasing polynomial.

Usage

 FMPMonotonicityCheck(b, lower = -20, upper = 20)

Arguments

b	A vector of 8 polynomial coefficients (b) for m(θ)=b_0 + b_1 θ + b_2 θ^2 + b_3 θ^3 + b_4 θ^4 + b_5 θ^5 + b_6 θ^6 + b_7 θ^7.
lower, upper	Theta bounds for monotonicity check.

Value

minDeriv

Minimum value of the derivative for the polynomial.

Author(s)

Niels Waller

Examples

## A set of candidate coefficients for an FMP model.
## These coefficients fail the test and thus
## should not be used with genFMPdata to generate
## item response data that are consistent with an 
## FMP model.
 b <- c(1.21, 1.87, -1.02, 0.18, 0.18, 0, 0, 0)
 FMPMonotonicityCheck(b)

FMP documentation built on May 2, 2019, 9:19 a.m.