This preview shows pages 1–2. Sign up to view the full content.
Sampling Distributions – Solutions
1
Suppose that medical researchers want to estimate the true proportion of all teenagers with
high blood pressure whose blood pressure would decrease if they took calcium supplements.
To test this, they plan a clinical trial in which n = 200 teenagers with high blood pressure will
be given calcium supplements.
a.
Suppose the clinical trial is completed, and 120 of the 200 participants experienced a decrease
in blood pressure.
i. What is the value of the sample proportion (also called the point estimate) p
ˆ
for this
sample?
p
ˆ
=
120/200 = 0.60
ii. Using the result found in part i, determine the value of the standard error of p
ˆ
.
Note
that in many situations we will not know the true parameter, p, and thus will substitute our sample
proportion for p in the calculation of the SE.
This formula then for the SE( p
ˆ
) when p is
unknown is:
n
)
p
ˆ
1
(
p
ˆ

SE( p
ˆ
) =
200
)
6
.
10
(
6
.
= 0.035
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview. Sign up
to
access the rest of the document.
This note was uploaded on 08/01/2011 for the course STAT 101 taught by Professor Thomas during the Spring '11 term at Pennsylvania State University, University Park.
 Spring '11
 Thomas

Click to edit the document details