Question

sherlock holmes Question 2. A wealthy philanthropist well-known in London's high society was murdered in his home. Sherlock Holmes finds a blood-stained golf club in a dumpster 2 blocks from the philanthropist's home. The blood test measurement on the golf club blood has value -14.2. Use the least squares prediction equation to estimate the age of the person whose blood is on the golf club (use 2 decimal places).

Question 3. Help Holmes solve this murder mystery by calculating a 99% prediction interval for the age of the person whose blood is on the golf club (use 2 decimal places). lower bound of prediction interval_______________ upper bound of prediction interval_______________ Blood Test Measure Age in Years

http://www.webassign.net/userimages/blood%20test%20human%20age.xls?db=v4net&id=331902

Answer 1

We Fit the simple linear regression model using Excel

SUMMARY OUTPUT
Regression Statistics
Multiple R	0.928555
R Square	0.862215
Adjusted R Square	0.861783
Standard Error	8.441812
Observations	321
ANOVA
	df	SS	MS	F	Significance F
Regression	1	142257.1	142257.1	1996.193	2.4E-139
Residual	319	22733.28	71.26419
Total	320	164990.3
	Coefficients	Standard Error	t Stat	P-value	Lower 95%	Upper 95%	Lower 95.0%	Upper 95.0%
Intercept	-28.3431	1.625332	-17.4384	2.67E-48	-31.5409	-25.1454	-31.5409	-25.1454
Blood Test Measure	-6.46363	0.144669	-44.6788	2.4E-139	-6.74825	-6.179	-6.74825	-6.179

Here the model fitting good(as Pvalue <0.05).

Both coefficent are also significant( P Value <0.05)

So,

Model is

Age=-28.3431-6.46363*Test Value

Q2:

if Test Value=-14.2

Age=-28.3431-6.46363*-14.2=63.44045

Q3:

n	321
df	319
mean(x)	-10.7524
x0	-14.2
Intercept	-28.3431
Slope	-6.46363
y_hat	63.4404
Sres	8.441812
SSx	3405.031
se	0.686126
t_Crit	2.591329
Lower	61.66242
Upper	65.21838

Formula Sheet:

Blood Test Measure	Age in Years
-15.49	78.2		n	=+COUNT(B2:B322)
-11.04	51.3		df	=+E2-2
-13.62	70.1		mean(x)	=AVERAGE(A2:A322)
-7.79	7.6		x0	=+-14.2
-14.84	77.9		Intercept	=+INTERCEPT(B2:B322,A2:A322)
-8.3	20.1		Slope	=+SLOPE(B2:B322,A2:A322)
-9.83	24.4		y_hat	=+E6+E7*E5
-15.12	65.7		Sres	=+STEYX(B2:B322,A2:A322)
-13.31	55		SSx	=+DEVSQ(A2:A322)
-14.66	72.5		se	=+E9*SQRT(1/E2+(E5-E4)^2/E10)
-15.77	63		t_Crit	=+TINV(0.01,E3)
-15	64.7		Lower	=+E8-E11*E12
-10.45	38.7		Upper	=+E8+E12*E11
-7.68	26.1
-15.93	76.2

lower bound of prediction interval___61.66____________ upper bound of prediction interval_______65.22________ Blood Test Measure