Compute Student's t-statistics from correlation coefficients

This function computes correlation coefficients and their corresponding Student's t-statistics between all pairs of series from two tree-ring datasets.

Usage

trs_tSt(x, y = NULL, min_overlap = 30, as_df = FALSE)

Arguments

x

A data frame of test tree-ring series in rwl format (years as rownames, series as columns). All columns must be numeric.

y

A data frame of reference tree-ring series in rwl format.

min_overlap

Integer. Minimum number of overlapping years required between series pairs to compute statistics. Must be >= 3. Default is 30.

as_df

Logical. If TRUE, returns results as data frames. If FALSE, returns as matrices. Default is TRUE.

Value

A list containing:

r

Correlation coefficients between series pairs

t

Student's t-statistics

overlap

Number of overlapping years between series pairs

Details

The function computes Pearson correlation coefficients between all pairs of series from the two input datasets, then converts these to Student's t-statistics using the formula: t = r * sqrt(n-2) / sqrt(1-r²), where n is the number of overlapping observations.

Examples

# Create sample data,
trs <- trs_pseudo_rwl(n_series = 5, series_length = c(80, 100), end_date = c(2010, 2020))
trs_tSt(trs)$t_St
#>       trs_1 trs_2 trs_3 trs_4 trs_5
#> trs_1   Inf 13.32 10.77 11.26 15.59
#> trs_2 13.32   Inf 13.04 13.24 13.28
#> trs_3 10.77 13.04   Inf 10.97 12.66
#> trs_4 11.26 13.24 10.97   Inf 13.84
#> trs_5 15.59 13.28 12.66 13.84   Inf