Problema Solution
In a set of 80 ACT scores, where the mean is 24 and the standard deviation is 6.08, (a) how many scores are expected to be lower than 17.92? (b) How many pf the 80 scores are expected to be below 36.16?
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(a)
z=(17.92 - 24)/6.08
z = -1.
P(z<-1)=0.1587
Number of scores expected to be lower than 17.92 out of 80 is 0.1587*80 =12.696 or approximately 13.
(b)
z=(36.16 - 24)/6.08
z = 2
P(z<2)=0.9772
Number of scores expected to be lower than 36.16 out of 80 is 80*0.9772 = 78.176 or approximately 78.