Sugar Bags Ae5F82
1. Problem statement: We have sugar bags filled with an average (mean) of 1004 g and a standard deviation of 2.4 g, assuming a normal distribution.
2. We want to find:
a) The percentage of bags containing less than 1000 g.
b) The number of bags (out of 890) containing between 1000 g and 1005 g.
3. Formula and rules:
For a normal distribution, the z-score is calculated as:
$$z = \frac{x - \mu}{\sigma}$$
where $x$ is the value, $\mu$ is the mean, and $\sigma$ is the standard deviation.
4. Part a) Calculate the percentage of bags with less than 1000 g:
$$z = \frac{1000 - 1004}{2.4} = \frac{-4}{2.4} = -1.6667$$
5. Using standard normal distribution tables or a calculator, find the cumulative probability for $z = -1.6667$:
$$P(Z < -1.6667) \approx 0.0478$$
This means approximately 4.78% of bags contain less than 1000 g.
6. Part b) Calculate the number of bags with sugar between 1000 g and 1005 g:
Calculate z-scores for both limits:
$$z_1 = \frac{1000 - 1004}{2.4} = -1.6667$$
$$z_2 = \frac{1005 - 1004}{2.4} = 0.4167$$
7. Find cumulative probabilities:
$$P(Z < -1.6667) \approx 0.0478$$
$$P(Z < 0.4167) \approx 0.6612$$
8. Probability that $Z$ is between $z_1$ and $z_2$:
$$P(-1.6667 < Z < 0.4167) = 0.6612 - 0.0478 = 0.6134$$
9. Number of bags in this range out of 890:
$$890 \times 0.6134 \approx 546$$
Final answers:
- a) 4.78%
- b) 546 bags