We have the following equations based on the given information:
1. The sum of probabilities: \(p + q + r + 0.4 = 1\)
2. The expected value: \(-3p + 2r + 4 \times 0.4 = 2.3\)
3. The variance: \((-3)^2p + 2^2r + 4^2 \times 0.4 - 2.3^2 = 3.01\)
From equation 1, we have:
\(p + q + r = 0.6\)
From equation 2, we simplify:
\(-3p + 2r = 0.7\)
From equation 3, we simplify:
\(9p + 4r = 1.9\)
Solving \(-3p + 2r = 0.7\) and \(9p + 4r = 1.9\) simultaneously:
Multiply the first equation by 2:
\(-6p + 4r = 1.4\)
Subtract from the second equation:
\(9p + 6p = 1.9 - 1.4\)
\(15p = 0.5\)
\(p = \frac{1}{30}\)
Substitute \(p\) back into \(-3p + 2r = 0.7\):
\(-3 \times \frac{1}{30} + 2r = 0.7\)
\(-0.1 + 2r = 0.7\)
\(2r = 0.8\)
\(r = \frac{2}{5}\)
Substitute \(p\) and \(r\) into \(p + q + r = 0.6\):
\(\frac{1}{30} + q + \frac{2}{5} = 0.6\)
\(q = 0.6 - 0.4 - 0.0333\)
\(q = \frac{1}{6}\)