The times, t t\,t minutes, for 80 tasks are grouped below.
| Time | 0<t≤100<t\leq100<t≤10 | 10<t≤2010<t\leq2010<t≤20 | 20<t≤3020<t\leq3020<t≤30 | 30<t≤5030<t\leq5030<t≤50 |
|---|---|---|---|---|
| Frequency | 8 | 24 | 32 | 16 |
Estimate the mean and standard deviation.
Use linear interpolation to estimate the 70th percentile.