The electricity company collected daily numbers of distribution network disturbance reports over 30 days. Summer intern Iina sent the information to her colleague Klaus, but in her haste, the observation numbers of the first three days were destroyed. The submitted material is below. Klaus remembered his previous university studies and decided to replace the missing three observations with the average of the observed numbers, thinking that this way the average would not change.

How many percent did the coefficient of variation of the material supplemented in this way change compared to if the correct numbers of the first three days 348, 327, and 314, which Tiina remembered to send a couple of days later, had been used?

Include a sign for a possible negative answer (the coefficient of variation decreased). Correct answer tolerance: relative error ±0.01.

238

376

252

209

263

249

205

211

343

270

329

292

338

259

293

327

237

257

322

291

287

282

300

283

348

244

258