The algebra test had a mean of 82 and a standard deviation of 8. What percentage of scores fall between 82 and 90.
Solution :
Given that ,
mean = = 82
standard deviation = = 8
P( 82 < x <90) = P[(82 - 82) / 8 ) < (x - ) / < (90 - 82) / 8) ]
= P( 0 < z < 1)
= P(z < 1 ) - P(z < 0)
Using z table,
= 0.8413 - 0.5
= 0.3413
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