An experiment to measure the toxicity of formaldehyde yielded the data
in the table below. The values show the percent, [math],
of rats surviving an exposure to formaldehyde at a concentration of
[math] (in parts per million, ppm) after [math] months.
| [math] | [math] | [math] | [math] | [math] | [math] |
[math] | 100 | 100 | 100 | 99 | 97 | 95 |
[math] | 100 | 99 | 98 | 97 | 95 | 92 |
[math] | 96 | 95 | 93 | 90 | 86 | 80 |
[math] | 96 | 93 | 82 | 70 | 58 | 36 |
(a)
Estimate [math]:
[math]
(b)
Estimate [math]:
[math]
(Be sure that you can give the practical meaning of these
two values in terms of formaldehyde toxicity.)
Solution: