Given that z is a standard normal random variable compute th

Given that z is a standard normal random variable, compute the following probabilities.

Find P(Z -0.71)

Find P(Z >0.21)

Find P(-1.98Z0.49)

Solution

a)

Using a table/technology, the left tailed area of this is          
          
P(z <   -0.71   ) =    0.238852068 [ANSWER]

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b)

Using a table/technology, the right tailed area of this is          
          
P(z >   0.21   ) =    0.416833837 [ANSWER]

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c)

z1 = lower z score =    -1.98      
z2 = upper z score =     0.49      
          
Using table/technology, the left tailed areas between these z scores is          
          
P(z < z1) =    0.023851764      
P(z < z2) =    0.687933051      
          
Thus, the area between them, by subtracting these areas, is          
          
P(z1 < z < z2) =    0.664081286   [ANSWER]