A group of 25 internet shoppers were asked how much they invest per year on the Internet. Their responses (in dollars) are given below.
| 418 |
379 |
77 |
212 |
378 |
| 363 |
434 |
348 |
245 |
341 |
| 331 |
356 |
423 |
330 |
247 |
| 351 |
151 |
220 |
383 |
257 |
| 307 |
297 |
448 |
391 |
210 |
Find out a 95% confidence interval for mean amount spent by all Internet shoppers