A technician recorded the age of 10 mobile phones and their current battery health percentage. The information is shown on the scatter graph.
| Age (months) | Battery Health (%) |
|---|---|
| 2 | 98 |
| 5 | 96 |
| 8 | 94 |
| 12 | 92 |
| 16 | 88 |
| 20 | 85 |
| 24 | 82 |
| 30 | 78 |
| 36 | 75 |
| 42 | 70 |
a.[1]
What type of correlation does the scatter graph show?
b.[2]
A different mobile phone has a battery health of 80%. Estimate the age of this mobile phone.