Final answer:
The z-score for an SAT score of 720 is 1.74, indicating it is relatively high. A math SAT score 1.5 standard deviations above the mean is 697.5. The person who took the ACT math test performed better based on z-scores.
Step-by-step explanation:
The question is asking about the distribution of scores in the math section of the SAT exam. The mean (µ) is 520 and the standard deviation (σ) is 115. To calculate the z-score for an SAT score of 720, we use the formula: z = (x - µ) / σ. Plugging in the given values, we have z = (720 - 520) / 115 = 1.74. This means the SAT score of 720 is 1.74 standard deviations above the mean. In the context of this situation, a score of 720 is relatively high compared to the average.
To find the math SAT score that is 1.5 standard deviations above the mean, we multiply the standard deviation by 1.5 and add it to the mean. So, x = µ + (1.5 * σ) = 520 + (1.5 *115) = 697.5. Therefore, a math SAT score of 697.5 is 1.5 standard deviations above the mean.
To determine who did better on their respective tests, we need to compare the scores to the mean and standard deviation of each test. For the SAT math test, the person scored 700, which is (700 - 514) / 117 = 1.59 standard deviations above the mean. For the ACT math test, the person scored 30, which is (30 - 21) / 5.3 = 1.7 standard deviations above the mean. Since a higher z-score means a higher relative score compared to the mean, the person who took the ACT math test did better in terms of their test score.