Purchase Solution

Biostatistics Problem to Reject or Accept Hypothesis

Not what you're looking for?

Ask Custom Question

I have attached a long regression problem that I completed most of. I'd like you to tell me what I did wrong including incorrect calculations. Comments and hints would be also be greatly appreciated as I am just learning this. I know this is a long problem so Im offering 12 credits. Thanks.

I have attached the problem as it was given to me (without my work) first. Then I attached my completed copy.
-----------
Assignment A, Module 3
Please fill in all of the blank spaces below. Due May 17, 2004. (15 points)
Obs# X Y X2 Y2 XY YCALC = a + bX YOBS - YCALC
1 22 120
2 20 115
3 23 100
4 21 100
5 20 110
6 24 145
7 24 140
8 27 180
9 23 125
10 28 210
11 23 120
12 26 160
13 25 150
14 29 225
15 30 200
16 28 175
17 27 180
18 23 130

:
Mean
n = number of X-Y pairs = (X)2 = (Y)2 =
df = (number of paired observations) - 2 = n - 2 =
b = {(XY) - [(X)(Y)/n]} =
(X2) - (X)2/n
or
b = {[n((XY))] - [(X)(Y)]}/{[n((X2))] - [(X)2]}
=

or
b = SSXY/SSX = ([(XY)] - [(X)(Y)/n])/([ (X2)] - [(X)2/n]) =

SSXY = [(XY)] - [(X)(Y)/n] =
SSX = [(X2)] - [(X)2/n] =

a = YMEAN - b(XMEAN) =

YCALC =

Module 3 Assignment A (Page 2)

Obs#
X
Y xi =
Xi - meanX
xi2 yi =
Yi - meanY
yi2
xiyi
1 22 120
2 20 115
3 23 100
4 21 100
5 20 110
6 24 145
7 24 140
8 27 180
9 23 125
10 28 210
11 23 120
12 26 160
13 25 150
14 29 225
15 30 200
16 28 175
17 27 180
18 23 130

:
Mean
s2
s

(sx)2 = [(Xi - meanX)2]/(n - 1) = [(xi2)]/(n - 1) =
(sy)2 = [(Yi - meanY)2]/(n - 1) = [(yi2)]/(n - 1) =
(sy·x)2 = (n - 1)[(sy)2 - (b2)(sx)2]/(n - 2) =

(sa)2 = [(sy·x)2/n] + {[(sy·x)2(meanX)2]/[(n - 1)(sx)2]}
=

sa =

(sb)2 = (sy·x)2/[(n - 1)(sx)2] =

sb =

Module 3 Assignment A (page 3):

Ho: b = 0.0000 : 0.05

tCALC = b/sb = df = n - 2 =

tTABLE(0.05) = therefore reject or fail to reject Ho that b = 0.0000 (choose one)

95% CI for b: b ± (tTABLE)(sb) =

therefore, 95% CI for b:
therefore, reject or fail to reject Ho that b = 0.000 (choose one)

...............
Ho: b = 1.0000 : 0.05

tCALC = (b - 1.0000)/sb =

tTABLE = therefore reject or fail to reject Ho that b = 1.0000 (choose one)

95% CI for b: b ± (tTABLE)(sb) =

therefore, 95% CI for b:
therefore, reject or fail to reject Ho that b = 1.0000 (choose one)

..............
Ho: b = 0.0000 : 0.05

FCALC = MS(R)/MS(E) = SS(R)/MS(E) = (b2)(SSX)/MS(E)
=

MS(E) = SS(E)/(n - 2) =
(or, MS(E) = [(sb)2](SSX) =
SS(E) = SS(TOTAL) - SS(R) =
SS(R) = (b2)(SSX) =
SS(TOTAL) = SSY = [(Y2)] - [(Y)2/n] =

FTable; 0.05; 1, (n - 2) = therefore reject or fail to reject Ho that b = 0.0000 (choose one)

Module 3 Assignment A (page 4):

95% Confidence Interval for regression line (at a given value of X):

95% CI: yCALC ± [(ttable)(syCALC)]

(syCALC)2 = [(sy·x)2/n] + {[(sy·x)2(X - meanX)2]/[(n - 1)(sx)2]}

if X = 28.6111:

(syCALC)2 =

(syCALC) =

YCALC =

yCALC ± [(ttable)(syCALC)] =

95% CI:

Module 3 Assignment A (page 5):

95% Confidence Interval for an individual calculated value of Y:

If, once the regression line has been calculated from a set of X-Y observations, it is desired to calculate Y for an individual whose value of X is 28.6111, the 95% CI for that individual's calculated value of Y is: yCALC ± [(ttable)(syNEW)]

(syNEW)2 = (sy·x)2 + [(sy·x)2/n] + {[(sy·x)2(X - meanX)2]/[(n - 1)(sx)2]}
=

(syNEW) =

YCALC =

yCALC ± [(ttable)(syNEW)] =

95% CI:

Module 3 Assignment A (page 6):

r = {(XY) - [(X)(Y)/n]} =
{[(X2) - (X)2/n] [(Y2) - (Y)2/n]}1/2

or
r = [(X - meanX)(Y - meanY)]/{[ (X - meanX)2][ (Y - meanY)2]}1/2
= [(xiyi)]/{[(xi2)][(yi2)]}1/2 =

or
r = (b)(sx)/(sy) =
or
r = SSXY/{(SSX)(SSY)}1/2 =

Ho: r = 0.0000 : 0.05

tCALC = r/sr =

sr = {(1 - r2)/(n - 2)}1/2 =

tTABLE(0.05) = therefore reject or fail to reject Ho that r = 0.000 (choose one)

...............
using table values for r:

Ho: r = 0.0000 : 0.05 rTABLE(0.05) =

therefore reject or fail to reject Ho that r = 0.0000 (choose one)

................
Using F-ratio for regression:

FCALC = MS(R)/MS(E) = SS(R)/MS(E) = (b2)(SSX)/MS(E)
=
FTable(0.05) =
therefore reject or fail to Ho that r = 0.0000 (choose one)

Purchase this Solution

Solution Summary

The expert examines biostatistic problems to reject or accept hypothesis tests. The F-ratio for regression is used.

Purchase this Solution


Free BrainMass Quizzes
Know Your Statistical Concepts

Each question is a choice-summary multiple choice question that presents you with a statistical concept and then 4 numbered statements. You must decide which (if any) of the numbered statements is/are true as they relate to the statistical concept.

Terms and Definitions for Statistics

This quiz covers basic terms and definitions of statistics.

Measures of Central Tendency

Tests knowledge of the three main measures of central tendency, including some simple calculation questions.

Measures of Central Tendency

This quiz evaluates the students understanding of the measures of central tendency seen in statistics. This quiz is specifically designed to incorporate the measures of central tendency as they relate to psychological research.