qstat: q-statistic
In rcosmo: Cosmic Microwave Background Data Analysis

Description Usage Arguments Details Value References Examples

This function returns an estimated q-statistic for the specified column intensities in a CMBDataFrame and the list of CMBWindows.

1	qstat(cmbdf, listwin, intensities = "I")

`cmbdf`	A `CMBDataFrame`.
`listwin`	A list of `CMBWindow`s
`intensities`	A `CMBDataFrame` column with measured values.

The q-statistics is used to measure spatial stratified heterogeneity and takes values in [0, 1]. It gives the percent of the variance of intensities explained by the stratification. 0 corresponds to no spatial stratified heterogeneity, 1 to perfect spatial stratified heterogeneity.

Estimated q-statistics for observations in a list of CMBWindows

Wang, J.F, Zhang, T.L, Fu, B.J. (2016). A measure of spatial stratified heterogeneity. Ecological Indicators. 67: 250–256.

## Download the map first
# downloadCMBMap(foreground = "smica", nside = 1024)
# df <- CMBDataFrame("CMB_map_smica1024.fits")
# cmbdf <- sampleCMB(df, sample.size = 1000)
# win1 <- CMBWindow(theta = c(0,pi/2,pi/2), phi = c(0,0,pi/2))
# win2 <- CMBWindow(theta = c(pi/2,pi,pi/2),  phi = c(0,0,pi/2))
#
# lw <- list(win1, win2)
# qstat(cmbdf, lw)