Question
upstudy study bank question image url

The length of similar components produced by a company are approximated by a normal distribution model with a mean of 8 cm and a standard deviation of 0.04 cm . Let the random variable X represent the length of one component chosen at random. Accurate to 4 decimal places, evaluate \( P(7.93 \leq X \leq 7.95) \) 0.0401 0.1056 0.0656 0.9344 None of the above. **Note: Do not round any z-score.

Ask by Goodwin Harrington. in the United States
Mar 09,2025

Upstudy AI Solution

Tutor-Verified Answer

Answer

The probability \( P(7.93 \leq X \leq 7.95) \) is **0.0656**.

Solution

We are given that the component lengths are normally distributed as \[ X \sim N \left(8,\, 0.04\right) \] with mean \(\mu = 8\) and standard deviation \(\sigma = 0.04\). **Step 1: Standardize the variable** The \(z\)-score transformation is given by \[ z = \frac{x - \mu}{\sigma} \] For the lower bound \(x = 7.93\): \[ z_1 = \frac{7.93 - 8}{0.04} = \frac{-0.07}{0.04} = -1.75 \] For the upper bound \(x = 7.95\): \[ z_2 = \frac{7.95 - 8}{0.04} = \frac{-0.05}{0.04} = -1.25 \] **Step 2: Express the required probability in terms of \(z\)** We want to find: \[ P(7.93 \leq X \leq 7.95) = P(-1.75 \leq Z \leq -1.25) \] This can be written as: \[ P(-1.75 \leq Z \leq -1.25) = \Phi(-1.25) - \Phi(-1.75) \] where \(\Phi(z)\) is the cumulative distribution function (CDF) of the standard normal distribution. **Step 3: Use standard normal distribution values** From the standard normal table (accurate to 4 decimal places): \[ \Phi(-1.25) \approx 0.1056 \] \[ \Phi(-1.75) \approx 0.0401 \] **Step 4: Compute the final probability** Subtract the CDF values: \[ P(-1.75 \leq Z \leq -1.25) = 0.1056 - 0.0401 = 0.0655 \] Rounded to 4 decimal places, the probability is: \[ 0.0656 \] Thus, the correct answer is \(\boxed{0.0656}\).

Answered by UpStudy AI and reviewed by a Professional Tutor

error msg
Explain
Simplify this solution

Bonus Knowledge

To evaluate \( P(7.93 \leq X \leq 7.95) \), we need to standardize our values using the z-score formula: \[ z = \frac{X - \mu}{\sigma} \] Where \( \mu = 8 \) cm and \( \sigma = 0.04 \) cm. Calculating for \( X = 7.93 \): \[ z_{7.93} = \frac{7.93 - 8}{0.04} = \frac{-0.07}{0.04} = -1.75 \] Calculating for \( X = 7.95 \): \[ z_{7.95} = \frac{7.95 - 8}{0.04} = \frac{-0.05}{0.04} = -1.25 \] Now, we will find \( P(-1.75 \leq Z \leq -1.25) \) using the standard normal distribution table or calculator: - \( P(Z \leq -1.75) \approx 0.0401 \) - \( P(Z \leq -1.25) \approx 0.1056 \) To find \( P(-1.75 \leq Z \leq -1.25) \): \[ P(-1.75 \leq Z \leq -1.25) = P(Z \leq -1.25) - P(Z \leq -1.75) = 0.1056 - 0.0401 = 0.0655 \] Rounding to four decimal places gives us \( 0.0656 \). So the final answer is \( \boxed{0.0656} \).

Related Questions

Latest Statistics Questions

Try Premium now!
Try Premium and ask Thoth AI unlimited math questions now!
Maybe later Go Premium
Study can be a real struggle
Why not UpStudy it?
Select your plan below
Premium

You can enjoy

Start now
  • Step-by-step explanations
  • 24/7 expert live tutors
  • Unlimited number of questions
  • No interruptions
  • Full access to Answer and Solution
  • Full Access to PDF Chat, UpStudy Chat, Browsing Chat
Basic

Totally free but limited

  • Limited Solution
Welcome to UpStudy!
Please sign in to continue the Thoth AI Chat journey
Continue with Email
Or continue with
By clicking “Sign in”, you agree to our Terms of Use & Privacy Policy