my book is confusing please show me how you got the answer. mean82 S=12 convert

my book is confusing please show me how you got the answer. mean82 S=12 convert to z score a. 70 b. 90 c. 106 d. 100 convert z scores back a. ) b. 12.10 c. +1.82 d. -.75 e. +.25 f. +3.10 IN a normal distribution what proportion fall a. above z +1.00 b.belowz-2.00 c. abovez+3.0 d. below z = 0 e. above z -1.28 below z -1.62 in normal dist. what proportion fall bet. a. z=-1.00 and z=+1.00 b. z=-1.50 and z=+1.50 c. z=_2.28 and z=0 d. z=0 and z=+.50 e. z=+.75 and z=1.25 f. z=-.80 and z=_1.60 In a norm dist what proportion fall outside limits z=-1.00 and z=+1.00 b. outside lim z=_.50 and z=+.50 c. outside limits z=-1.26 and z=+1.83 IN normal dist what z scores a. enclose the middle 99% of cases b. middle 95%c. enclose middle 75% of cases d. enclose middle 50% of cases In a normal dist what is the z score a. above which the top 5% of cases fall b. above the top 1% cases fall c. below which bottom 5% case fall d. below which the bottom 75% of cases fall. Please explain simply.