Answer:
D)
Step-by-step explanation:
ASSUMING NORMAL DISTRIBUTION, LESS THAN 10% AT LOWER END
OF 15.34 MEANS [DENOTING MEAN BY M AND Standard Deviation. BY S]
M±AS=20%....................M-AS=15.34
FOR 20% LEVEL .......A=1.281........FROM TABLES
M-1.281×S=15.34............................1
SIMILARLY
M±BS=40%...................M+BS=16.31
FOR 40% LEVEL .............B=0.841...................FROM TABLES
M+0.841×S=16.31.............................2
EQN.2 - EQN.1
2.122×S=0.97
S=0.457=0.46
M=15.926= 15.93
HENCE, D IS THE ANSWER
that is D. μ = 15.93, σ =.46
It is 8y4 becuze 8*2=64 and 4*2=16 and u *2 becuze *2 means square root sorry if I'm wrong :)
