Changes in version 0.2.1                        

Bug fix

  - NAMESPACE: Removed sample, runif, and setNames from
    importFrom(stats, ...). These are base:: functions and are always
    available without import. Listing them under stats:: caused the
    warning: object 'sample' is not exported by 'namespace:stats' on
    devtools::load_all() and R CMD CHECK.

  - Added correct @importFrom stats coef lm qt sd var and @importFrom
    utils head read.csv roxygen2 tags to R/zzz.R so that
    devtools::document() regenerates the NAMESPACE without the base:: /
    stats:: confusion.

                        Changes in version 0.2.0                        

New features

  - Added NRMSampling.Rproj RStudio project file for streamlined
    development with devtools, roxygen2, and testthat integration.
  - stratified_sample() now accepts a named integer vector for
    n_per_stratum, enabling Neyman (optimal) or any user-defined
    allocation.
  - pps_sample() now attaches .inclusion_prob (n * p_i) to output, ready
    for direct use with ht_estimator().
  - plot_summary() now handles all-numeric data frames when vars = NULL
    without requiring explicit column names.
  - carbon_stock_estimate() now validates carbon_fraction range and
    documents the IPCC (2006) default of 0.47.
  - Added sampling_efficiency() for quantitative comparison of two
    sampling designs via relative efficiency (RE = Var1 / Var2).
  - All spatial functions now provide informative installation messages
    if sf or terra are not available, rather than an opaque error.

Bug fixes

  - purposive_sample(): condition evaluation now uses with() instead of
    eval(parse(...)) on the global environment, preventing accidental
    access to objects outside the data frame.
  - systematic_sample(): fixed an edge case where k = nrow(data) would
    select only one unit rather than erroring.
  - quota_sample(): now silently caps quota to stratum size instead of
    erroring when quota exceeds available units.
  - regression_estimator(): now requires at least 3 complete
    observations before fitting and raises an informative error.

Documentation

  - .Rbuildignore updated to exclude NRMSampling.Rproj and .Rproj.user/
    from the CRAN source bundle.
  - .gitignore expanded with comprehensive R, RStudio, and OS entries.
  - All roxygen2 @examples verified to run in under 5 seconds.
  - cran-comments.md updated to reflect v0.2.0 test environments.

                        Changes in version 0.1.0                        

Initial CRAN release

Probability Sampling

  - srs_sample() -- Simple random sampling with/without replacement.
  - stratified_sample() -- Equal, proportional, or Neyman allocation.
  - systematic_sample() -- Fixed-interval systematic sampling.
  - cluster_sample() -- Single-stage cluster sampling.
  - pps_sample() -- Probability-proportional-to-size sampling.

Non-Probability Sampling

  - convenience_sample() -- First-n convenience sample.
  - purposive_sample() -- Condition-based purposive sampling.
  - quota_sample() -- Fixed-quota non-random selection.

Estimation

  - estimate_mean(), estimate_total() -- Mean and total estimators.
  - estimate_variance(), estimate_se() -- Variance and SE with fpc.
  - estimate_ci() -- t-based confidence intervals.
  - ratio_estimator() -- Ratio estimate of population total.
  - regression_estimator() -- Regression-adjusted mean estimate.
  - ht_estimator(), ht_variance() -- Horvitz-Thompson estimator and
    variance.
  - stratified_estimator() -- Weighted stratified mean estimator.

NRM Utilities

  - biomass_estimate() -- Total and mean biomass from plot data.
  - soil_loss_estimate() -- Total and mean soil loss estimation.
  - carbon_stock_estimate() -- Carbon stock from biomass.
  - plot_summary() -- Descriptive statistics for numeric columns.
  - sampling_efficiency() -- Relative efficiency of two designs.

Spatial Sampling (sf + terra)

  - to_sf_points(), spatial_random_sample(),
    spatial_systematic_sample(), spatial_stratified_sample(),
    spatial_cluster_sample(), raster_stratified_sample(),
    raster_pps_sample(), extract_raster_values(),
    spatial_biomass_estimate(), plot_sampling(), plot_sampling_gg().

Datasets

  - sample_nrm -- 100-plot synthetic NRM field dataset.
  - sample_spatial -- 100-observation geo-referenced NRM dataset.