IDNLearn.com: Your trusted platform for finding precise and reliable answers. Ask your questions and receive reliable and comprehensive answers from our dedicated community of professionals.

Find the probabilities using the normal distribution.

a. Between [tex]$z=0$[/tex] and [tex]$z=1.97$[/tex]

b. Between [tex][tex]$z=0.79$[/tex][/tex] and [tex]$z=1.28$[/tex]

c. To the left of [tex]$z=1.22$[/tex]

d. To the right of [tex][tex]$z=-1.9$[/tex][/tex]

e. To the left of [tex]$z=-2.15$[/tex] or to the right of [tex]$z=1.6$[/tex]

f. [tex][tex]$P(z\ \textgreater \ 2.83)$[/tex][/tex]

g. [tex]$P(-0.05\ \textless \ z\ \textless \ 1.10)$[/tex]


Sagot :

Sure, let's break down each part of the problem step-by-step:

### Part a: Between [tex]\( z = 0 \)[/tex] and [tex]\( z = 1.97 \)[/tex]

We want to find the probability that a standard normal variable [tex]\( Z \)[/tex] falls between 0 and 1.97. This is calculated as the difference between the cumulative distribution function (CDF) values at these two points:

[tex]\[ P(0 \leq Z \leq 1.97) = \Phi(1.97) - \Phi(0) \][/tex]

Given the numerical result:

[tex]\[ P(0 \leq Z \leq 1.97) = 0.4755808147197774 \][/tex]

### Part b: Between [tex]\( z = 0.79 \)[/tex] and [tex]\( z = 1.28 \)[/tex]

We want to find the probability that a standard normal variable [tex]\( Z \)[/tex] falls between 0.79 and 1.28:

[tex]\[ P(0.79 \leq Z \leq 1.28) = \Phi(1.28) - \Phi(0.79) \][/tex]

Given the numerical result:

[tex]\[ P(0.79 \leq Z \leq 1.28) = 0.11449131620919506 \][/tex]

### Part c: To the left of [tex]\( z = 1.22 \)[/tex]

We want to find the probability that a standard normal variable [tex]\( Z \)[/tex] is less than 1.22:

[tex]\[ P(Z \leq 1.22) = \Phi(1.22) \][/tex]

Given the numerical result:

[tex]\[ P(Z \leq 1.22) = 0.8887675625521654 \][/tex]

### Part d: To the right of [tex]\( z = -1.9 \)[/tex]

We want to find the probability that a standard normal variable [tex]\( Z \)[/tex] is greater than -1.9:

[tex]\[ P(Z \geq -1.9) = 1 - \Phi(-1.9) \][/tex]

Given the numerical result:

[tex]\[ P(Z \geq -1.9) = 0.9712834401839981 \][/tex]

### Part e: To the left of [tex]\( z = -2.15 \)[/tex] or to the right of [tex]\( z = 1.6 \)[/tex]

We need to find two probabilities and sum them up:

1. The probability [tex]\( Z \)[/tex] is less than -2.15:
[tex]\[ P(Z \leq -2.15) = \Phi(-2.15) \][/tex]

2. The probability [tex]\( Z \)[/tex] is greater than 1.6:
[tex]\[ P(Z \geq 1.6) = 1 - \Phi(1.6) \][/tex]

So the total probability is:
[tex]\[ P(Z \leq -2.15) + P(Z \geq 1.6) = \Phi(-2.15) + (1 - \Phi(1.6)) \][/tex]

Given the numerical result:

[tex]\[ P(Z \leq -2.15 \text{ or } Z \geq 1.6) = 0.07057689909064849 \][/tex]

### Part f: [tex]\( P(z > 2.83) \)[/tex]

We want to find the probability that a standard normal variable [tex]\( Z \)[/tex] is greater than 2.83:

[tex]\[ P(Z \geq 2.83) = 1 - \Phi(2.83) \][/tex]

Given the numerical result:

[tex]\[ P(Z \geq 2.83) = 0.0023274002067315003 \][/tex]

### Part g: [tex]\( P(-0.05 < z < 1.10) \)[/tex]

We want to find the probability that a standard normal variable [tex]\( Z \)[/tex] falls between -0.05 and 1.10:

[tex]\[ P(-0.05 \leq Z \leq 1.10) = \Phi(1.10) - \Phi(-0.05) \][/tex]

Given the numerical result:

[tex]\[ P(-0.05 \leq Z \leq 1.10) = 0.3842727448919898 \][/tex]

So, these are the detailed step-by-step solutions for the given probabilities using the standard normal distribution.