In and exam a score of 58 was 2 standard deviations below mean and score of 98 was 3 standard deviations above mean. What was the mean?
58<---d---><---d--->mean<---d---><---d---><---d--->98For a certain examination, a score of 58 was 2 standard deviations below the mean, and a score of 98 was 3 standard deviations above the mean. What is the mean score for the examination.
1) 74
2) 76
3) 78
4) 80
5)82
As the figure above shows, there are a total of 5 standard deviations between 58 and 98.
Thus, d = (98-58)/5 = 8.
Since 58 is 2 standard deviations BELOW the mean, the mean = 58+d+d = 58+8+8 = 74.
The correct answer is A.
