Answer:
68%
Step-by-step explanation:
The attached normal table shows area under the standard normal curve that are to the left of a particular z-score.
To find the area between two z-scores, say [tex]z_1 < z_2[/tex], find the area to the left of [tex]z_2[/tex] then subtract the area to the left of [tex]z_1[/tex]. That difference is the area between the two z-scores.
38 minutes has a z-score [tex]z_1=\frac{38-42}{4}=-1[/tex]
46 minutes has a z-score [tex]z_2\frac{46-42}{4}=1[/tex]
Find z= 1.0 in the table. The area in that row is .8413.
Find z=-1.0 in the table. The area in that row is .1587.
The difference, .8413 - .1587 = .6826 is the area under the normal curve between z=-1 and z=1.
.6826 is about 68%
