1. **State the problem:** We are given a normal distribution of newborn baby weights with mean $\mu = 3.55$ kg and standard deviation $\sigma = 0.73$ kg. We need to find the weights corresponding to given z-scores. 2. **Formula:** The z-score formula relates a value $x$ to the mean and standard deviation as: $$ z = \frac{x - \mu}{\sigma} $$ Rearranged to find $x$: $$ x = z \times \sigma + \mu $$ 3. **Calculate for (a) $z = -1.9$:** $$ x = (-1.9) \times 0.73 + 3.55 $$ $$ x = -1.387 + 3.55 $$ $$ x = 2.163 $$ Rounded to the nearest tenth: $$ x \approx 2.2 \text{ kilograms} $$ 4. **Calculate for (b) $z = 1.4$:** $$ x = 1.4 \times 0.73 + 3.55 $$ $$ x = 1.022 + 3.55 $$ $$ x = 4.572 $$ Rounded to the nearest tenth: $$ x \approx 4.6 \text{ kilograms} $$ **Final answers:** (a) 2.2 kilograms (b) 4.6 kilograms