If Pz Solution1 This is the middle area between z and z By s

Solution

1.

This is the middle area between -z and z.

By symmetry, the area to the left of -z is (1-0.796)/2 = 0.102.

Thus, by table/technology,

-z = -1.270237622

Thus,

z = 1.270237622 [ANSWER]

[If you use Excel, you can type

=NORMSINV(0.102)

to get the critical -z.]

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2.

z1 = lower z score =    -2.35      
z2 = upper z score =     -0.37      
          
Using table/technology, the left tailed areas between these z scores is          
          
P(z < z1) =    0.009386706      
P(z < z2) =    0.355691245      
          
Thus, the area between them, by subtracting these areas, is          
          
P(z1 < z < z2) =    0.34630454   [ANSWER]  

[You can use the function =NORMSDIST(z) to get the left tailed area of a z score.]