Answer:
1 standard deviation
Step-by-step explanation:
Given that :
IQs as measured by the Wechsler Adult Intelligence Scale are approximately Normal with:
Mean = 100
Standard deviation = 15
About 84% of people will have IQs below 115 because:
84% = 0.84
From z - table, 0.84 corresponds to a z- score of about 0.995
0.995 = 1. 00
The z-score gives the number of standard deviations by which a raw score is above or below the average or mean value.
Raw score = 115
Mean = 100
Standard deviation (sd) = 15
Mean + number of sd's
100 + 1(sd)
100 + 1(15) = 100 + 15 = 115
