A school gives an entry exam for admission. Suppose the score of this exam follows a normal distribution N(400, 60). This year, the school decides to admit students who score in the top 30%. Suppose a student scored 428 on the test. Will the student be admitted? Explain your reasoning.

Glencoe Algebra 1, Student Edition, 9780079039897, 0079039898, 2018
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Chapter10: Statistics
Section10.4: Distributions Of Data
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**Admission Criteria Based on Entry Exam Scores**

A school gives an entry exam for admission. Suppose the score of this exam follows a normal distribution N(400, 60). This year, the school decides to admit students who score in the top 30%. Suppose a student scored 428 on the test. Will the student be admitted? Explain your reasoning.

---

In this context, we are dealing with a normal distribution with a mean (μ) of 400 and a standard deviation (σ) of 60. We need to find out if a score of 428 is within the top 30% of this distribution.

### Steps to Determine Admission:

1. **Convert the Score to a Z-Score:**
   The Z-score formula is given by:
   \[
   Z = \frac{(X - \mu)}{\sigma}
   \]
   Where:
   - \( X \) is the raw score (428 in this case).
   - \( \mu \) is the mean score (400).
   - \( \sigma \) is the standard deviation (60).

   Substituting the values:
   \[
   Z = \frac{(428 - 400)}{60} \approx 0.467
   \]

2. **Find the Percentile:**
   The Z-score of 0.467 corresponds to a percentile in the standard normal distribution table. Using a Z-table or statistical software, a Z-score of 0.467 corresponds approximately to the 68th percentile.

3. **Determine Admission:**
   The school admits students who score in the top 30%. This means that these students need to be in the 70th percentile or above (since 100% - 30% = 70%).

Since a score of 428 corresponds to the 68th percentile, which is below the 70th percentile threshold, the student will not be admitted.

### Final Answer:

No, the student will not be admitted, as their score of 428 does not fall within the top 30% of the distribution.
Transcribed Image Text:**Admission Criteria Based on Entry Exam Scores** A school gives an entry exam for admission. Suppose the score of this exam follows a normal distribution N(400, 60). This year, the school decides to admit students who score in the top 30%. Suppose a student scored 428 on the test. Will the student be admitted? Explain your reasoning. --- In this context, we are dealing with a normal distribution with a mean (μ) of 400 and a standard deviation (σ) of 60. We need to find out if a score of 428 is within the top 30% of this distribution. ### Steps to Determine Admission: 1. **Convert the Score to a Z-Score:** The Z-score formula is given by: \[ Z = \frac{(X - \mu)}{\sigma} \] Where: - \( X \) is the raw score (428 in this case). - \( \mu \) is the mean score (400). - \( \sigma \) is the standard deviation (60). Substituting the values: \[ Z = \frac{(428 - 400)}{60} \approx 0.467 \] 2. **Find the Percentile:** The Z-score of 0.467 corresponds to a percentile in the standard normal distribution table. Using a Z-table or statistical software, a Z-score of 0.467 corresponds approximately to the 68th percentile. 3. **Determine Admission:** The school admits students who score in the top 30%. This means that these students need to be in the 70th percentile or above (since 100% - 30% = 70%). Since a score of 428 corresponds to the 68th percentile, which is below the 70th percentile threshold, the student will not be admitted. ### Final Answer: No, the student will not be admitted, as their score of 428 does not fall within the top 30% of the distribution.
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