1. **State the problem:** We have 30 reaction times (in milliseconds) of adult females responding to an auditory stimulus. We need to group these data into 8 classes and find the frequency for each class. 2. **Find the range of the data:** - Minimum value: $295$ - Maximum value: $514$ - Range = $514 - 295 = 219$ 3. **Calculate class width:** - Number of classes = 8 - Class width = $\frac{\text{Range}}{\text{Number of classes}} = \frac{219}{8} = 27.375$ - We round up to $28$ for easier class intervals. 4. **Determine class intervals:** - Start from minimum value $295$. - Classes: 1. $295$ to $295 + 28 - 1 = 322$ 2. $323$ to $350$ 3. $351$ to $378$ 4. $379$ to $406$ 5. $407$ to $434$ 6. $435$ to $462$ 7. $463$ to $490$ 8. $491$ to $518$ 5. **Count frequencies:** Count how many data points fall into each class. Data: 429, 295, 382, 337, 514, 423, 385, 430, 372, 310, 442, 387, 351, 472, 385, 413, 443, 425, 304, 453, 310, 308, 324, 412, 450, 388, 318, 357, 507, 416 - Class 1 (295-322): 295, 310, 304, 310, 308, 318 → 6 - Class 2 (323-350): 337, 324 → 2 - Class 3 (351-378): 351, 357, 372 → 3 - Class 4 (379-406): 382, 385, 385, 387, 388 → 5 - Class 5 (407-434): 413, 412, 416, 423, 425, 429, 430 → 7 - Class 6 (435-462): 442, 443, 450, 453 → 4 - Class 7 (463-490): 472 → 1 - Class 8 (491-518): 507, 514 → 2 6. **Final frequency table:** | Class Interval | Frequency | |----------------|-----------| | 295 - 322 | 6 | | 323 - 350 | 2 | | 351 - 378 | 3 | | 379 - 406 | 5 | | 407 - 434 | 7 | | 435 - 462 | 4 | | 463 - 490 | 1 | | 491 - 518 | 2 | This completes the frequency distribution for the 8 classes.