Probability of generating pounds between 27 and 31 per month = 62.47%

Explanation:

Z1 = (Higher range of pounds - Average pounds) / Standard deviation

= (31 - 28) / 2

= 1.5

Z2 = (Lower range of pounds - Average pounds) / Standard deviation

= (27 - 28) / 2

= -0.5

Probability = P(X < 31) - P(X < 27)

= P( Z < 1.5) - P(z < -0.5)

= 0.9332 - 0.3085

= 0.6247 or 62.47%

Note:

Using Z table following values are obtained:

Z value at 1.5 = 0.9332

Z value at (-0.5) = 0.3085