Question

Find the probability that a high school student gets an exam score between 74 and 78. Assume that the exam scores are normally distributed with a average of 82 and a STD(standard deviation) of 4 (Draw the normal curve with labels and shade the appropriate area) 1 i. T:- 1 B 1 U x P % !•

Answer 1

µ =    82                                  
σ =    4                                  
we need to calculate probability for ,                                      
P (   74.00   < X <   78.00   )                      
=P( (74-82)/4 < (X-µ)/σ < (78-82)/4 )                                      
                                      
P (    -2.000   < Z <    -1.000   )                       
= P ( Z <    -1.000   ) - P ( Z <   -2.00   ) =    0.1587   -    0.0228   =    0.1359   (answer)

68 70 72 74 76 78 80 82 4 6 88 90 92 4 96