lifeTable_boot_test: Paired Bootstrap Test Between Two Life Tables

In insectecol: Insect Ecology Data Analysis Toolkit

Paired Bootstrap Test Between Two Life Tables

Description

Compares the life table parameters of two cohorts with the paired bootstrap test used by TWOSEX-MSChart: both cohorts are resampled independently B times, the differences d = parameter(group 1) - parameter(group 2) are formed replicate by replicate, and the 95 percent percentile interval of the differences is inspected. Following the convention of the life table literature, the difference is considered significant when the confidence interval of the difference does not include zero.

Usage

lifeTable_boot_test(lt1, lt2, B = 1e+05, seed = NULL, conf.level = 0.95)

Arguments

lt1, lt2	life_table objects (e.g. two treatments or two host plants) returned by lifeTable_read or lifeTable_build.
B	Integer; number of bootstrap replicates per group (default 100000, the TWOSEX-MSChart standard).
seed	Integer; seed for the random number generator; the session state is restored when the function exits.
conf.level	Numeric; confidence level of the intervals of the differences (default 0.95).

Details

The two cohorts are resampled independently, so they do not need to have the same number of individuals. The parameters compared are those of lifeTable_bootstrap that occur in BOTH cohorts; if the stage structures differ, only the common parameters are compared and a warning is issued. A bootstrap p-value is reported in addition to the interval test: 2 * min(P(d <= 0), P(d >= 0)) over the valid replicates. Replicates in which a parameter is undefined in either group (e.g. no female drawn) are dropped from the comparison.

Value

A data frame with one row per compared parameter:

Parameter	parameter name (as in lifeTable_bootstrap)
Boot_mean_1, Boot_mean_2	bootstrap means of the two groups
Diff	mean of the bootstrap differences (group 1 minus group 2)
CI_low, CI_high	percentile interval of the differences
Significant	logical; TRUE when the interval excludes zero
P_bootstrap	two-sided bootstrap p-value

The attribute groups contains the file names of the two cohorts.

References

Meyer, J. S., Ingersoll, C. G., McDonald, L. L. and Boyce, M. S. (1986) Estimating uncertainty in population growth rates: jackknife vs. bootstrap. Ecological Modelling 29, 251-271.

Chi, H., You, M. S., Atlihan, R., Smith, C. L., Kavousi, A., Ozgokce, M. S., Guncan, A. and Tuan, S. J. (2020) Age-stage, two-sex life table: an introduction to theory, data analysis, and application. Entomologia Generalis 40(2), 103-124.

See Also

lifeTable_bootstrap for the standard errors of a single cohort.

Examples

f <- system.file("extdata", "lifetable_example.csv", package = "insectecol")
lt1 <- lifeTable_read(f)

## compare the full cohort with its first half (demo only - a real
## comparison would use two different treatments)
lt2 <- lt1
lt2$data <- lt1$data[1:12, ]
rownames(lt2$data) <- NULL
lt2$file_name <- "Example (first half)"

## B = 100000 is the recommended setting for publications; a smaller
## B is used here so that the example runs fast
lifeTable_boot_test(lt1, lt2, B = 2000, seed = 1)

insectecol documentation built on Oct. 5, 2026, 5:08 p.m.