#
# 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.
# 
#-----

cip = 0.95
cip = 0.98 
alpha = 1 - cip

n = 10

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

b1 = -1.5
sYdotX = 35    # this is an estimate of the common variance (the same for all x's) 
sXX = 140

print( b1 - t * sqrt( sYdotX / sXX ) )
print( b1 + t * sqrt( sYdotX / sXX ) )