5. (40 points in total) A study was conducted to determine the effects of sleep deprivation on people's ability to solve problems without sleep. A total of 10 subjects participated in the study, two at each of five sleep deprivation levels - 8, 12, 16, 20, and 24 hours. After his or her specified sleep deprivation period, each subject was administered a set of simple addition problems, and the number of errors was recorded. These results were obtained:
| Number of Hours without Sleep, x | 8 | 12 | 16 | 20 | 24 |
| -------------------------------- | -- | -- | -- | -- | -- |
| Number of Errors, y | 8,6 | 6,10 | 8,14 | 14,12 | 16,12 |
| | | | | | |
【題組】(d). (5 points) How do you describe the strength of the relationship between y and x?