In this problem, assume that the distribution of differences is approximately normal. Note : For degrees of freedom d . f . not in the Student's t table, use the closest d . f . that is smaller . In...

In this problem, assume that the distribution of differences is approximately normal.
Note: For degrees of freedom
d.f. not in the Student's
t
table, use the closest
d.f. that is
smaller. In some situations, this choice of
d.f. may increase the
P-value by a small amount and therefore produce a slightly more "conservative" answer.



A survey of houses and traditional hogans was made in a number of different regions of the modern Navajo Indian Reservation. The following table is the result of a random sample of eight regions on the Navajo Reservation.

Does this information indicate that the population mean number of inhabited houses is greater than that of hogans on the Navajo Reservation? Use a 5% level of significance. (Let
d
= houses − hogans.)