Construct a 90% confidence interval for u1 - u2 with the sample statistics for mean calorie content of 2 bakeries' specialty pies and confidence interval construction formula below. Assume the populations are approximately normal and equal variances.
Bakery A: x1= 1857 calories, s1=130 calories, n1=13
Bakery B: x2= 1618 calories, s2=209 calories, n2=11