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| 1 | +<!-- |
| 2 | +
|
| 3 | +@license Apache-2.0 |
| 4 | +
|
| 5 | +Copyright (c) 2025 The Stdlib Authors. |
| 6 | +
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| 7 | +Licensed under the Apache License, Version 2.0 (the "License"); |
| 8 | +you may not use this file except in compliance with the License. |
| 9 | +You may obtain a copy of the License at |
| 10 | +
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| 11 | + http://www.apache.org/licenses/LICENSE-2.0 |
| 12 | +
|
| 13 | +Unless required by applicable law or agreed to in writing, software |
| 14 | +distributed under the License is distributed on an "AS IS" BASIS, |
| 15 | +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 16 | +See the License for the specific language governing permissions and |
| 17 | +limitations under the License. |
| 18 | +
|
| 19 | +--> |
| 20 | + |
| 21 | +<!-- lint disable max-heading-length --> |
| 22 | + |
| 23 | +# dztest |
| 24 | + |
| 25 | +> Compute a one-sample Z-test for a double-precision floating-point strided array. |
| 26 | +
|
| 27 | +<section class="intro"> |
| 28 | + |
| 29 | +TODO: add introduction |
| 30 | + |
| 31 | +</section> |
| 32 | + |
| 33 | +<!-- /.intro --> |
| 34 | + |
| 35 | +<section class="usage"> |
| 36 | + |
| 37 | +## Usage |
| 38 | + |
| 39 | +```javascript |
| 40 | +var dztest = require( '@stdlib/stats/strided/dztest' ); |
| 41 | +``` |
| 42 | + |
| 43 | +#### dztest( N, alternative, alpha, mu, sigma, x, strideX, out ) |
| 44 | + |
| 45 | +Computes a one-sample Z-test for a double-precision floating-point strided array. |
| 46 | + |
| 47 | +```javascript |
| 48 | +var Float64Array = require( '@stdlib/array/float64' ); |
| 49 | +var Results = require( '@stdlib/stats/base/ztest/one-sample/results/float64' ); |
| 50 | + |
| 51 | +var x = new Float64Array( [ 4.0, 4.0, 6.0, 6.0, 5.0 ] ); |
| 52 | + |
| 53 | +var results = new Results(); |
| 54 | +var out = dztest( x.length, 'two-sided', 0.05, 0.0, 1.0, x, 1, results ); |
| 55 | +// returns {...} |
| 56 | + |
| 57 | +var bool = ( out === results ); |
| 58 | +// returns true |
| 59 | +``` |
| 60 | + |
| 61 | +The function has the following parameters: |
| 62 | + |
| 63 | +- **N**: number of indexed elements. |
| 64 | +- **alternative**: [alternative hypothesis][@stdlib/stats/base/ztest/alternatives]. |
| 65 | +- **alpha**: significance level. |
| 66 | +- **mu**: mean value under the null hypothesis. |
| 67 | +- **sigma**: known standard deviation. |
| 68 | +- **x**: input [`Float64Array`][@stdlib/array/float64]. |
| 69 | +- **strideX**: stride length for `x`. |
| 70 | +- **out**: output [results object][@stdlib/stats/base/ztest/one-sample/results/float64]. |
| 71 | + |
| 72 | +The `N` and stride parameters determine which elements in the strided array are accessed at runtime. For example, to perform a one-sample Z-test over every other element in `x`, |
| 73 | + |
| 74 | +```javascript |
| 75 | +var Float64Array = require( '@stdlib/array/float64' ); |
| 76 | +var Results = require( '@stdlib/stats/base/ztest/one-sample/results/float64' ); |
| 77 | + |
| 78 | +var x = new Float64Array( [ 4.0, 0.0, 4.0, 0.0, 6.0, 0.0, 6.0, 0.0, 5.0, 0.0 ] ); |
| 79 | + |
| 80 | +var results = new Results(); |
| 81 | +var out = dztest( x.length, 'two-sided', 0.05, 0.0, 1.0, x, 2, results ); |
| 82 | +// returns {...} |
| 83 | + |
| 84 | +var bool = ( out === results ); |
| 85 | +// returns true |
| 86 | +``` |
| 87 | + |
| 88 | +Note that indexing is relative to the first index. To introduce an offset, use [`typed array`][mdn-typed-array] views. |
| 89 | + |
| 90 | +<!-- eslint-disable stdlib/capitalized-comments --> |
| 91 | + |
| 92 | +```javascript |
| 93 | +var Float64Array = require( '@stdlib/array/float64' ); |
| 94 | +var Results = require( '@stdlib/stats/base/ztest/one-sample/results/float64' ); |
| 95 | + |
| 96 | +var x0 = new Float64Array( [ 0.0, 4.0, 4.0, 6.0, 6.0, 5.0 ] ); |
| 97 | +var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element |
| 98 | + |
| 99 | +var results = new Results(); |
| 100 | +var out = dztest( x.length, 'two-sided', 0.05, 0.0, 1.0, x1, 1, results ); |
| 101 | +// returns {...} |
| 102 | + |
| 103 | +var bool = ( out === results ); |
| 104 | +// returns true |
| 105 | +``` |
| 106 | + |
| 107 | +#### dztest.ndarray( N, alternative, alpha, mu, sigma, x, strideX, offsetX, out ) |
| 108 | + |
| 109 | +Computes a one-sample Z-test for a double-precision floating-point strided array using alternative indexing semantics. |
| 110 | + |
| 111 | +```javascript |
| 112 | +var Float64Array = require( '@stdlib/array/float64' ); |
| 113 | +var Results = require( '@stdlib/stats/base/ztest/one-sample/results/float64' ); |
| 114 | + |
| 115 | +var x = new Float64Array( [ 4.0, 4.0, 6.0, 6.0, 5.0 ] ); |
| 116 | + |
| 117 | +var results = new Results(); |
| 118 | +var out = dztest.ndarray( x.length, 'two-sided', 0.05, 0.0, 1.0, x, 1, 0, results ); |
| 119 | +// returns {...} |
| 120 | + |
| 121 | +var bool = ( out === results ); |
| 122 | +// returns true |
| 123 | +``` |
| 124 | + |
| 125 | +The function has the following additional parameters: |
| 126 | + |
| 127 | +- **offsetX**: starting index for `x`. |
| 128 | + |
| 129 | +While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying buffer, the offset parameter supports indexing semantics based on a starting index. For example, to perform a one-sample Z-test over every other element in `x` starting from the second element |
| 130 | + |
| 131 | +```javascript |
| 132 | +var Float64Array = require( '@stdlib/array/float64' ); |
| 133 | +var Results = require( '@stdlib/stats/base/ztest/one-sample/results/float64' ); |
| 134 | + |
| 135 | +var x = new Float64Array( [ 0.0, 4.0, 0.0, 4.0, 0.0, 6.0, 0.0, 6.0, 0.0, 5.0 ] ); |
| 136 | + |
| 137 | +var results = new Results(); |
| 138 | +var out = dztest.ndarray( x.length, 'two-sided', 0.05, 0.0, 1.0, x, 2, 1, results ); |
| 139 | +// returns {...} |
| 140 | + |
| 141 | +var bool = ( out === results ); |
| 142 | +// returns true |
| 143 | +``` |
| 144 | + |
| 145 | +</section> |
| 146 | + |
| 147 | +<!-- /.usage --> |
| 148 | + |
| 149 | +<section class="notes"> |
| 150 | + |
| 151 | +</section> |
| 152 | + |
| 153 | +<!-- /.notes --> |
| 154 | + |
| 155 | +<section class="examples"> |
| 156 | + |
| 157 | +## Examples |
| 158 | + |
| 159 | +<!-- eslint no-undef: "error" --> |
| 160 | + |
| 161 | +```javascript |
| 162 | +var normal = require( '@stdlib/random/array/normal' ); |
| 163 | +var Results = require( '@stdlib/stats/base/ztest/one-sample/results/float64' ); |
| 164 | +var dztest = require( '@stdlib/stats/strided/dztest' ); |
| 165 | + |
| 166 | +var x = normal( 1000, 0.0, 1.0, { |
| 167 | + 'dtype': 'float64' |
| 168 | +}); |
| 169 | + |
| 170 | +var results = new Results(); |
| 171 | +var out = dztest( x.length, 'two-sided', 0.05, 0.0, 1.0, x, 1, results ); |
| 172 | +// returns {...} |
| 173 | + |
| 174 | +console.log( out.toString() ); |
| 175 | +``` |
| 176 | + |
| 177 | +</section> |
| 178 | + |
| 179 | +<!-- /.examples --> |
| 180 | + |
| 181 | +<!-- C interface documentation. --> |
| 182 | + |
| 183 | +* * * |
| 184 | + |
| 185 | +<section class="c"> |
| 186 | + |
| 187 | +## C APIs |
| 188 | + |
| 189 | +<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. --> |
| 190 | + |
| 191 | +<section class="intro"> |
| 192 | + |
| 193 | +</section> |
| 194 | + |
| 195 | +<!-- /.intro --> |
| 196 | + |
| 197 | +<!-- C usage documentation. --> |
| 198 | + |
| 199 | +<section class="usage"> |
| 200 | + |
| 201 | +### Usage |
| 202 | + |
| 203 | +```c |
| 204 | +#include "stdlib/stats/strided/dztest.h" |
| 205 | +``` |
| 206 | + |
| 207 | +#### stdlib_strided_dztest( N, alternative, alpha, mu, sigma, \*X, strideX, \*results ) |
| 208 | + |
| 209 | +Computes a one-sample Z-test for a double-precision floating-point strided array. |
| 210 | + |
| 211 | +```c |
| 212 | +#include "stdlib/stats/base/ztest/one-sample/results/float64.h" |
| 213 | +#include "stdlib/stats/base/ztest/alternatives.h" |
| 214 | + |
| 215 | +struct stdlib_stats_ztest_one_sample_float64_results results = { |
| 216 | + .rejected = false, |
| 217 | + .alpha = 0.0, |
| 218 | + .alternative = STDLIB_STATS_ZTEST_TWO_SIDED, |
| 219 | + .pValue = 0.0, |
| 220 | + .statistic = 0.0, |
| 221 | + .ci = { 0.0, 0.0 }, |
| 222 | + .nullValue = 0.0, |
| 223 | + .sd = 0.0 |
| 224 | +}; |
| 225 | + |
| 226 | +const double x[] = { 4.0, 4.0, 6.0, 6.0, 5.0 }; |
| 227 | + |
| 228 | +stdlib_strided_dztest( 5, STDLIB_STATS_ZTEST_TWO_SIDED, 0.05, 0.0, 1.0, x, 1, &results ); |
| 229 | +``` |
| 230 | +
|
| 231 | +The function accepts the following arguments: |
| 232 | +
|
| 233 | +- **N**: `[in] CBLAS_INT` number of indexed elements. |
| 234 | +- **alternative**: `[in] enum STDLIB_STATS_ZTEST_ALTERNATIVE` [alternative hypothesis][@stdlib/stats/base/ztest/alternatives]. |
| 235 | +- **alpha**: significance level. |
| 236 | +- **mu**: value of the mean under the null hypothesis. |
| 237 | +- **sigma** known standard deviation. |
| 238 | +- **X**: `[in] double*` input array. |
| 239 | +- **strideX**: `[in] CBLAS_INT` stride length for `X`. |
| 240 | +- **results**: `[out] struct stdlib_stats_ztest_one_sample_results_float64*` output [results object][@stdlib/stats/base/ztest/one-sample/results/float64]. |
| 241 | +
|
| 242 | +```c |
| 243 | +void stdlib_strided_dztest( const CBLAS_INT N, const enum STDLIB_STATS_ZTEST_ALTERNATIVE alternative, const double alpha, const double mu, const double sigma, const double *X, const CBLAS_INT strideX, struct stdlib_stats_ztest_one_sample_float64_results *results ); |
| 244 | +``` |
| 245 | + |
| 246 | +#### stdlib_strided_dztest_ndarray( N, alternative, alpha, mu, sigma, \*X, strideX, offsetX, \*results ) |
| 247 | + |
| 248 | +Computes a one-sample Z-test for a double-precision floating-point strided array using alternative indexing semantics. |
| 249 | + |
| 250 | +```c |
| 251 | +#include "stdlib/stats/base/ztest/one-sample/results/float64.h" |
| 252 | +#include "stdlib/stats/base/ztest/alternatives.h" |
| 253 | + |
| 254 | +struct stdlib_stats_ztest_one_sample_float64_results results = { |
| 255 | + .rejected = false, |
| 256 | + .alpha = 0.0, |
| 257 | + .alternative = STDLIB_STATS_ZTEST_TWO_SIDED, |
| 258 | + .pValue = 0.0, |
| 259 | + .statistic = 0.0, |
| 260 | + .ci = { 0.0, 0.0 }, |
| 261 | + .nullValue = 0.0, |
| 262 | + .sd = 0.0 |
| 263 | +}; |
| 264 | + |
| 265 | +const double x[] = { 4.0, 4.0, 6.0, 6.0, 5.0 }; |
| 266 | + |
| 267 | +stdlib_strided_dztest_ndarray( 5, STDLIB_STATS_ZTEST_TWO_SIDED, 0.05, 0.0, 1.0, x, 1, 0, &results ); |
| 268 | +``` |
| 269 | +
|
| 270 | +The function accepts the following arguments: |
| 271 | +
|
| 272 | +- **N**: `[in] CBLAS_INT` number of indexed elements. |
| 273 | +- **alternative**: `[in] enum STDLIB_STATS_ZTEST_ALTERNATIVE` [alternative hypothesis][@stdlib/stats/base/ztest/alternatives]. |
| 274 | +- **alpha**: significance level. |
| 275 | +- **mu**: value of the mean under the null hypothesis. |
| 276 | +- **sigma** known standard deviation. |
| 277 | +- **X**: `[in] double*` input array. |
| 278 | +- **strideX**: `[in] CBLAS_INT` stride length for `X`. |
| 279 | +- **offsetX**: `[in] CBLAS_INT` starting index for `X`. |
| 280 | +- **results**: `[out] struct stdlib_stats_ztest_one_sample_results_float64*` output [results object][@stdlib/stats/base/ztest/one-sample/results/float64]. |
| 281 | +
|
| 282 | +```c |
| 283 | +void stdlib_strided_dztest_ndarray( const CBLAS_INT N, const enum STDLIB_STATS_ZTEST_ALTERNATIVE alternative, const double alpha, const double mu, const double sigma, const double *X, const CBLAS_INT strideX, const CBLAS_INT offsetX, struct stdlib_stats_ztest_one_sample_float64_results *results ); |
| 284 | +``` |
| 285 | + |
| 286 | +</section> |
| 287 | + |
| 288 | +<!-- /.usage --> |
| 289 | + |
| 290 | +<!-- C API usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. --> |
| 291 | + |
| 292 | +<section class="notes"> |
| 293 | + |
| 294 | +</section> |
| 295 | + |
| 296 | +<!-- /.notes --> |
| 297 | + |
| 298 | +<!-- C API usage examples. --> |
| 299 | + |
| 300 | +<section class="examples"> |
| 301 | + |
| 302 | +### Examples |
| 303 | + |
| 304 | +```c |
| 305 | +#include "stdlib/stats/strided/dztest.h" |
| 306 | +#include "stdlib/stats/base/ztest/one-sample/results/float64.h" |
| 307 | +#include "stdlib/stats/base/ztest/alternatives.h" |
| 308 | +#include <stdbool.h> |
| 309 | +#include <stdio.h> |
| 310 | + |
| 311 | +int main( void ) { |
| 312 | + // Create a strided array: |
| 313 | + const double x[] = { 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 }; |
| 314 | + |
| 315 | + // Specify the number of elements: |
| 316 | + const int N = 4; |
| 317 | + |
| 318 | + // Specify the stride length: |
| 319 | + const int strideX = 2; |
| 320 | + |
| 321 | + // Initialize a results object: |
| 322 | + struct stdlib_stats_ztest_one_sample_float64_results results = { |
| 323 | + .rejected = false, |
| 324 | + .alpha = 0.0, |
| 325 | + .alternative = STDLIB_STATS_ZTEST_TWO_SIDED, |
| 326 | + .pValue = 0.0, |
| 327 | + .statistic = 0.0, |
| 328 | + .ci = { 0.0, 0.0 }, |
| 329 | + .nullValue = 0.0, |
| 330 | + .sd = 0.0 |
| 331 | + }; |
| 332 | + |
| 333 | + // Compute a z-test: |
| 334 | + stdlib_strided_dztest( N, STDLIB_STATS_ZTEST_TWO_SIDED, 0.05, 5.0, 3.0, x, strideX, &results ); |
| 335 | + |
| 336 | + // Print the result: |
| 337 | + printf( "Statistic: %lf\n", results.statistic ); |
| 338 | + printf( "Null hypothesis was %s\n", ( results.rejected ) ? "rejected" : "not rejected" ); |
| 339 | +} |
| 340 | +``` |
| 341 | +
|
| 342 | +</section> |
| 343 | +
|
| 344 | +<!-- /.examples --> |
| 345 | +
|
| 346 | +</section> |
| 347 | +
|
| 348 | +<!-- /.c --> |
| 349 | +
|
| 350 | +<section class="references"> |
| 351 | +
|
| 352 | +</section> |
| 353 | +
|
| 354 | +<!-- /.references --> |
| 355 | +
|
| 356 | +<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. --> |
| 357 | +
|
| 358 | +<section class="related"> |
| 359 | +
|
| 360 | +</section> |
| 361 | +
|
| 362 | +<!-- /.related --> |
| 363 | +
|
| 364 | +<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. --> |
| 365 | +
|
| 366 | +<section class="links"> |
| 367 | +
|
| 368 | +[variance]: https://en.wikipedia.org/wiki/Variance |
| 369 | +
|
| 370 | +[@stdlib/array/float64]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/array/float64 |
| 371 | +
|
| 372 | +[@stdlib/stats/base/ztest/alternatives]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/stats/base/ztest/alternatives |
| 373 | +
|
| 374 | +[@stdlib/stats/base/ztest/one-sample/results/float64]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/stats/base/ztest/one-sample/results/float64 |
| 375 | +
|
| 376 | +[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray |
| 377 | +
|
| 378 | +</section> |
| 379 | +
|
| 380 | +<!-- /.links --> |
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