Math Problem Statement

Find the following probabilities for the standard normal curve.

  (a) P (1.32 < z < 2.18).   Answer: Answer 1 Question 1

  (b) P (-1.61 < z  < 2.36).  Answer: Answer 2 Question 1

  (c) P (z > -.65).  Answer:  Answer 3 Question 1

Solution

To find the probabilities for the standard normal distribution, we use the cumulative distribution function (CDF) of the standard normal curve.

Solution:

(a) P(1.32<z<2.18)P(1.32 < z < 2.18)

P(1.32<z<2.18)=P(Z<2.18)P(Z<1.32)P(1.32 < z < 2.18) = P(Z < 2.18) - P(Z < 1.32) Using the standard normal table: P(Z<2.18)=0.9854,P(Z<1.32)=0.9066P(Z < 2.18) = 0.9854, \quad P(Z < 1.32) = 0.9066 P(1.32<Z<2.18)=0.98540.9066=0.0788P(1.32 < Z < 2.18) = 0.9854 - 0.9066 = \mathbf{0.0788}

(b) P(1.61<z<2.36)P(-1.61 < z < 2.36)

P(1.61<z<2.36)=P(Z<2.36)P(Z<1.61)P(-1.61 < z < 2.36) = P(Z < 2.36) - P(Z < -1.61) From the standard normal table: P(Z<2.36)=0.9909,P(Z<1.61)=0.0537P(Z < 2.36) = 0.9909, \quad P(Z < -1.61) = 0.0537 P(1.61<Z<2.36)=0.99090.0537=0.9372P(-1.61 < Z < 2.36) = 0.9909 - 0.0537 = \mathbf{0.9372}

(c) P(z>0.65)P(z > -0.65)

P(Z>0.65)=1P(Z<0.65)P(Z > -0.65) = 1 - P(Z < -0.65) From the standard normal table: P(Z<0.65)=0.2578P(Z < -0.65) = 0.2578 P(Z>0.65)=10.2578=0.7422P(Z > -0.65) = 1 - 0.2578 = \mathbf{0.7422}


Final Answers:

  • (a) P(1.32<z<2.18)=0.0788P(1.32 < z < 2.18) = 0.0788
  • (b) P(1.61<z<2.36)=0.9372P(-1.61 < z < 2.36) = 0.9372
  • (c) P(z>0.65)=0.7422P(z > -0.65) = 0.7422

Would you like me to explain any step in more detail?


Related Questions:

  1. How do you calculate probabilities for a normal distribution that is not standard?
  2. What is the probability of P(2<z<1.5)P(-2 < z < 1.5) in a standard normal curve?
  3. How do you find the z-score given a probability?
  4. How do you use a standard normal table to find left-tailed probabilities?
  5. What is the difference between one-tailed and two-tailed probabilities?

Tip:

If you don't have a z-table handy, you can use statistical software like Excel (NORM.S.DIST function) or a scientific calculator to find cumulative probabilities!

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Math Problem Analysis

Mathematical Concepts

Probability
Standard Normal Distribution
Z-Scores
Cumulative Distribution Function (CDF)

Formulas

P(a < z < b) = P(Z < b) - P(Z < a)
P(Z > a) = 1 - P(Z < a)

Theorems

Standard Normal Distribution Table
Cumulative Distribution Function for the Standard Normal Curve

Suitable Grade Level

Grades 10-12