Answer:
(a) P(0 ≤ Z ≤ 2.87)=0.498
(b) P(0 ≤ Z ≤ 2)=0.477
(c) P(−2.20 ≤ Z ≤ 0)=0.486
(d) P(−2.20 ≤ Z ≤ 2.20)=0.972
(e) P(Z ≤ 1.01)=0.844
(f) P(−1.95 ≤ Z)=0.974
(g) P(−1.20 ≤ Z ≤ 2.00)=0.862
(h) P(1.01 ≤ Z ≤ 2.50)=0.150
(i) P(1.20 ≤ Z)=0.115
(j) P(|Z| ≤ 2.50)=0.988
Step-by-step explanation:
(a) P(0 ≤ Z ≤ 2.87)
In this case, this is equal to the difference between P(z<2.87) and P(z<0). The last term is substracting because is the area under the curve that is included in P(z<2.87) but does not correspond because the other condition is that z>0.
![P(0 \leq z \leq 2.87)= P(z](https://tex.z-dn.net/?f=P%280%20%5Cleq%20z%20%5Cleq%202.87%29%3D%20P%28z%3C2.87%29-P%28z%3C0%29%3D0.998-0.5%3D0.498)
(b) P(0 ≤ Z ≤ 2)
This is the same case as point a.
![P(0 \leq z \leq 2)= P(z](https://tex.z-dn.net/?f=P%280%20%5Cleq%20z%20%5Cleq%202%29%3D%20P%28z%3C2%29-P%28z%3C0%29%3D0.977-0.5%3D0.477)
(c) P(−2.20 ≤ Z ≤ 0)
This is the same case as point a.
![P(-2.2 \leq z \leq 0)= P(z](https://tex.z-dn.net/?f=P%28-2.2%20%5Cleq%20z%20%5Cleq%200%29%3D%20P%28z%3C0%29-P%28z%3C-2.2%29%3D0.5-0.014%3D0.486)
(d) P(−2.20 ≤ Z ≤ 2.20)
This is the same case as point a.
![P(-2.2 \leq z \leq 2.2)= P(z](https://tex.z-dn.net/?f=P%28-2.2%20%5Cleq%20z%20%5Cleq%202.2%29%3D%20P%28z%3C2.2%29-P%28z%3C-2.2%29%3D0.986-0.014%3D0.972)
(e) P(Z ≤ 1.01)
This can be calculated simply as the area under the curve for z from -infinity to z=1.01.
![P(z\leq1.01)=0.844](https://tex.z-dn.net/?f=P%28z%5Cleq1.01%29%3D0.844)
(f) P(−1.95 ≤ Z)
This is best expressed as P(z≥-1.95), and is calculated as the area under the curve that goes from z=-1.95 to infininity.
It also can be calculated, thanks to the symmetry in z=0 of the standard normal distribution, as P(z≥-1.95)=P(z≤1.95).
![P(z\geq -1.95)=0.974](https://tex.z-dn.net/?f=P%28z%5Cgeq%20-1.95%29%3D0.974)
(g) P(−1.20 ≤ Z ≤ 2.00)
This is the same case as point a.
![P(-1.20 \leq z \leq 2.00)= P(z](https://tex.z-dn.net/?f=P%28-1.20%20%5Cleq%20z%20%5Cleq%202.00%29%3D%20P%28z%3C2%29-P%28z%3C-1.2%29%3D0.977-0.115%3D0.862)
(h) P(1.01 ≤ Z ≤ 2.50)
This is the same case as point a.
![P(1.01 \leq z \leq 2.50)= P(z](https://tex.z-dn.net/?f=P%281.01%20%5Cleq%20z%20%5Cleq%202.50%29%3D%20P%28z%3C2.5%29-P%28z%3C1.01%29%3D0.994-0.844%3D0.150)
(i) P(1.20 ≤ Z)
This is the same case as point f.
![P(z\geq 1.20)=0.115](https://tex.z-dn.net/?f=P%28z%5Cgeq%201.20%29%3D0.115)
(j) P(|Z| ≤ 2.50)
In this case, the z is expressed in absolute value. If z is positive, it has to be under 2.5. If z is negative, it means it has to be over -2.5. So this probability is translated to P|Z| < 2.50)=P(-2.5<z<2.5) and then solved from there like in point a.
![P(|z|](https://tex.z-dn.net/?f=P%28%7Cz%7C%3C2.5%29%3DP%28-2.5%3Cz%3C2.5%29%3DP%28z%3C2.5%29-P%28z%3C-2.5%29%5C%5C%5C%5CP%28%7Cz%7C%3C2.5%29%3D0.994-0.006%3D0.988)