JMP Analysis of Blood Pressure Data
Enter the data into two columns:
Group – Data Type is Character, Modeling Type is Nominal
Blood Pressure – Data Type is Numeric, Modeling Type is Continuous
Go to Basic in the JMP Starter
Click on Oneway
Enter Blood Pressure for the Y, Response and Group for the X, Grouping
Click on OK
Oneway Analysis of Blood Pressure By Group
135
Blood Pressure
130
125
120
115
110
105
1
2
Group
Click on the Red Triangle next to Oneway Analysis of Blood Pressure By Group
1
Means/ANOVA/Pooled t – Performs and ANalysis of VAriance and two-sample t-test
assuming equal variances. (STAT 401)
t Test
2-1
Assuming equal variances
Difference
Std Err Dif
Upper CL Dif
Lower CL Dif
Confidence
9.600
4.643
20.307
-1.107
0.95
t Ratio
DF
Prob > |t|
Prob > t
Prob < t
2.067506
8
0.0725
0.0363*
0.9637
The value of the t-test statistic is 2.068 with a one-sided P-value of 0.0363. Group 2 has
a sample mean that is larger than the sample mean for Group 1 and that difference is
statistically significant. We can infer that individuals, similar to those who participated
in this experiment, will have a lower average blood pressure level if they eat a diet with
no more than 2.400 mg/day of salt (sodium) compared to individuals who eat a diet with
4,000 to 6,000 mg/day of salt (sodium).
Means and Std Dev – Calculates and displays sample means and sample standard
deviations.
Means and Std Deviations
Level
Number
Mean
1
5
117.000
2
5
126.600
Std Dev Std Err Mean Lower 95%
7.74597
3.4641
107.38
6.91375
3.0919
118.02
Upper 95%
126.62
135.18
t Test – Performs a two-sample t-test assuming unequal variances. (STAT 101)
t Test
2-1
Assuming unequal variances
Difference
Std Err Dif
Upper CL Dif
Lower CL Dif
Confidence
9.600
4.643
20.331
-1.131
0.95
t Ratio
DF
Prob > |t|
Prob > t
Prob < t
2.067506
7.898832
0.0730
0.0365*
0.9635
2