Assume that adults have IQ scores that are normally distributed with a mean of 101.3 and a standard deviation of 17. Find the probability that a randomly selected adult has an IQ greater than 133.7. (Hint: Draw a graph.) The probability that a randomly selected adult from this group has an IQ greater than 133.7 is (Round to four decimal places as needed.)

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**Probability and Normal Distribution of IQ Scores**

Assume that adults have IQ scores that are normally distributed with a mean of 101.3 and a standard deviation of 17. Find the probability that a randomly selected adult has an IQ greater than 133.7. (Hint: Draw a graph.)

**Solution:**

To find the probability that a randomly selected adult from this group has an IQ greater than 133.7, follow these steps:

1. **Calculate the Z-score:**
   The Z-score is a measure of how many standard deviations an element is from the mean. The formula to calculate the Z-score is:
   \[
   Z = \frac{X - \mu}{\sigma}
   \]
   where:
   - \( X \) is the value (133.7)
   - \( \mu \) is the mean (101.3)
   - \( \sigma \) is the standard deviation (17)

   Substituting the given values:
   \[
   Z = \frac{133.7 - 101.3}{17}
   \]
   \[
   Z = \frac{32.4}{17}
   \]
   \[
   Z \approx 1.9059
   \]

2. **Find the probability for the Z-score:**
   Use the standard normal distribution table (Z-table) to find the probability corresponding to the Z-score of 1.9059. The Z-table gives the probability that a value is less than the given Z-score.

   The probability corresponding to \( Z = 1.9059 \) is approximately 0.9718.

3. **Calculate the desired probability:**
   To find the probability that a randomly selected adult has an IQ greater than 133.7, subtract the table value from 1:
   \[
   P(X > 133.7) = 1 - P(X \leq 133.7)
   \]
   \[
   P(X > 133.7) = 1 - 0.9718
   \]
   \[
   P(X > 133.7) \approx 0.0282
   \]

   Therefore, the probability that a randomly selected adult from this group has an IQ greater than 133.7 is approximately **0.0282** (rounded to four decimal places).

**Graphical Representation:**

On a graph of the
Transcribed Image Text:**Probability and Normal Distribution of IQ Scores** Assume that adults have IQ scores that are normally distributed with a mean of 101.3 and a standard deviation of 17. Find the probability that a randomly selected adult has an IQ greater than 133.7. (Hint: Draw a graph.) **Solution:** To find the probability that a randomly selected adult from this group has an IQ greater than 133.7, follow these steps: 1. **Calculate the Z-score:** The Z-score is a measure of how many standard deviations an element is from the mean. The formula to calculate the Z-score is: \[ Z = \frac{X - \mu}{\sigma} \] where: - \( X \) is the value (133.7) - \( \mu \) is the mean (101.3) - \( \sigma \) is the standard deviation (17) Substituting the given values: \[ Z = \frac{133.7 - 101.3}{17} \] \[ Z = \frac{32.4}{17} \] \[ Z \approx 1.9059 \] 2. **Find the probability for the Z-score:** Use the standard normal distribution table (Z-table) to find the probability corresponding to the Z-score of 1.9059. The Z-table gives the probability that a value is less than the given Z-score. The probability corresponding to \( Z = 1.9059 \) is approximately 0.9718. 3. **Calculate the desired probability:** To find the probability that a randomly selected adult has an IQ greater than 133.7, subtract the table value from 1: \[ P(X > 133.7) = 1 - P(X \leq 133.7) \] \[ P(X > 133.7) = 1 - 0.9718 \] \[ P(X > 133.7) \approx 0.0282 \] Therefore, the probability that a randomly selected adult from this group has an IQ greater than 133.7 is approximately **0.0282** (rounded to four decimal places). **Graphical Representation:** On a graph of the
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