Stat 257: Solutions to Assignment #3
(3.1) Let X denote the assessed yields, and let Y denote the actual yields. Our goal is to estimate
YT . In addition to the data clearly given in the problem, note that we also know the following:
N = 280, n = 25, and
Stat 257: (Selected) Solutions to Assignment #5
(5.2) We begin with the observation that
M
L
M
M
(Yij Y )2 + 2
i=1 j=1
L
L
(Yij Y )(Yik Y ) =
i=1 j<k
(Yij Y )(Yik Y ).
()
i=1 j=1 k=1
The two expressions on the left side of () are easy to deal with. From e
Stat 257: Solutions to Assignment #2
(2.1) In order to calculate y, we must pool the averages from each of the two simple random samples
remembering to weight by the appropriate sample sizes. That is,
n1
n2
300
500
y +
y =
2.98 +
3.42 = 3.255.
n1 + n2 1
Stat 257: Solutions to Assignment #4
(4.1) From the data given in the problem, we have N = 235 public libraries which are grouped
into three strata: strata 1 consists of N1 = 74 small libraries, strata 2 consists of N2 = 133 medium
libraries, and strata 3