In: Statistics and Probability
SAT scores are normally distributed with a mean of 1200 and a variance of 1600. What is the probability that a random sample of 16 scores will yield a mean score less than 1192.5?
Given that ,
mean = 
 = 1200
variance = 1600
standard deviation = 
 = 
1600 = 40
n = 16

= 1200 and

= 
 / 
 n = 40 / 
 16 = 10
P(
< 1192.5) = P((
- 
) / 
< (1192.5 - 1200) / 10) = P(Z< -0.75) = 0.2266
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