#
#Epage 182
#
# Written by:
# -- 
# John L. Weatherwax                2009-04-21
# 
# email: wax@alum.mit.edu
# 
# Please send comments and especially bug reports to the
# above email address.
# 
#-----

n = 41
barY = 10
barX = 12
SXY = 100
SXX = 400
s2 = 144     # this is an estimate of the common variance (the same for all x's)

b1 = SXY / SXX
b0 = barY - b1 * barX

ci = 0.90
alpha = 1 - ci
t = qt( 1 - alpha/2, n-2 )

print( b1 - t * sqrt( s2 / SXX ) ) 
print( b1 + t * sqrt( s2 / SXX ) )