a)
Sample Size, n= 16
Standard Deviation, ?= 2500
P ( s > 3000 ) = 1 - P( s ? 3000)=1 -
P(X²?(n-1)s²/?²) = 1 - P(X² ? 15*3000²/2500² )
=1 - P(X² ? 21.6 )
=1 - 0.88127 =
0.1187
[excel function: "=1 - CHISQ.DIST(21.6,15,TRUE)
b)
Sample Size, n= 16
population Standard Deviation, ?= 2500
P ( s< 1500 )= P(X²?(n-1)s²/?²) =
=P(X² < 5.4 ) =
0.0118
[excel function: "=CHISQ.DIST(5.4,15,TRUE) ]
