- Mon Mar 21, 2011 1:14 pm
- Forum: Statistics
- Topic: mean time taken to solve prob (need help w/ starting)
- Replies:
**1** - Views:
**3399**

Hi zorro; i) 120 to 154 represents -2.06666 sd below the mean and .26666 sd above the mean. The area under the curve that represents the standard normal curve is: \Large \int_{-2.0666}^{0.2666} \ \frac{e^{-\frac{x^2}{2}}}{\sqrt{2 \pi }} \, dx \approx \ .5857 Meaning that 58.57% of the students fall ...

- Mon Mar 21, 2011 12:15 pm
- Forum: Discrete Math
- Topic: counting paths in three-dimensional space
- Replies:
**2** - Views:
**2906**

Hi kt5016; Your formula is indeed correct for (0,0,0) to (m,m,m). It exactly coincides with the number of paths of length 3n in an m x m x m grid from (0,0,0) to (m,m,m) and is called De Bruijn's s(3,n). Your fomula for (0,0,0) to (m,m,m) becomes \Large {3m \choose m } { 2m \choose m } {m \choose m ...