Normal Area
1. Stating the problem: Find areas under the standard normal curve for various z-values, specifically areas above or below certain z-scores or between regions.
2. Area above z = 1.46: The area to the right of z = 1.46 is found by $1 - P(Z \leq 1.46)$.
Looking up $P(Z \leq 1.46)$ (the cumulative distribution function for z = 1.46), we find approximately 0.9279.
So, area above is $$1 - 0.9279 = 0.0721.$$
3. Area below z = -0.58: The area to the left of z = -0.58 is simply $P(Z \leq -0.58)$.
Looking up $P(Z \leq -0.58)$, we get approximately 0.2810.
4. Area greater than z = -1.32: This is the area to the right of z = -1.32, calculated by $$1 - P(Z \leq -1.32).$$
Lookup gives $P(Z \leq -1.32) \approx 0.0934$.
So, area is $$1 - 0.0934 = 0.9066.$$
5. Area at least z = 1 (which means greater than or equal to 1): This area is the same as area above z = 1:
$$1 - P(Z \leq 1) = 1 - 0.8413 = 0.1587.$$
Final answers:
- Area above z = 1.46: 0.0721
- Area below z = -0.58: 0.2810
- Area greater than z = -1.32: 0.9066
- Area at least z = 1: 0.1587
These values reflect proportions of the total area under the standard normal curve based on z-scores.