Final answer:
Isabella's score of 99 cannot be definitively placed relative to the mean without additional information about the mean or distribution of scores in Ms. Johnson's test.
Step-by-step explanation:
Without additional information about the class mean score or the distribution of scores, we cannot definitively determine where Isabella's score of 99 places her relative to the class mean. However, if the class mean were less than 99, Isabella's score would be above the mean. If the class mean were greater than 99, her score would be below the mean. If the class mean were exactly 99, her score would be equal to the mean. Scores on a test can often be analyzed using tools like z-scores, percentiles, and levels of significance to determine how they compare to the rest of the distribution.
For example, Susan's z-score of 2.0 tells us she scored two standard deviations above the mean, and being in a certain percentile, like the 90th, indicates a score that is better than 90 percent of the others. Without knowing where the 99 falls in relation to the distribution of scores in Isabella's class, the exact comparison to the mean cannot be determined from the provided information.