Note: See Calculating Various Statistical Intervals in the SAS/QC Sample Library.
The following statements create the data set Cans
, which contains measurements (in ounces) of the fluid weights of 100 drink cans. The filling process is assumed to be in
statistical control.
data Cans; label Weight = "Fluid Weight (ounces)"; input Weight @@; datalines; 12.07 12.02 12.00 12.01 11.98 11.96 12.04 12.05 12.01 11.97 12.03 12.03 12.00 12.04 11.96 12.02 12.06 12.00 12.02 11.91 12.05 11.98 11.91 12.01 12.06 12.02 12.05 11.90 12.07 11.98 12.02 12.11 12.00 11.99 11.95 11.98 12.05 12.00 12.10 12.04 12.06 12.04 11.99 12.06 11.99 12.07 11.96 11.97 12.00 11.97 12.09 11.99 11.95 11.99 11.99 11.96 11.94 12.03 12.09 12.03 11.99 12.00 12.05 12.04 12.05 12.01 11.97 11.93 12.00 11.97 12.13 12.07 12.00 11.96 11.99 11.97 12.05 11.94 11.99 12.02 11.95 11.99 11.91 12.06 12.03 12.06 12.05 12.04 12.03 11.98 12.05 12.05 12.11 11.96 12.00 11.96 11.96 12.00 12.01 11.98 ;
Note that this data set is introduced in Computing Descriptive Statistics of PROC CAPABILITY and General Statements. The analysis in that section provides evidence that the weight measurements are normally distributed.
By default, the INTERVALS statement computes and prints the six intervals described in the entry for the METHODS= option. The following statements tabulate these intervals for the variable Weight
:
title 'Statistical Intervals for Fluid Weight'; proc capability data=Cans noprint; intervals Weight; run;
The intervals are displayed in Figure 5.27.
Figure 5.25: Statistical Intervals for Weight
Statistical Intervals for Fluid Weight |
Approximate Prediction Interval Containing All of k Future Observations |
|||
---|---|---|---|
Confidence | k | Prediction Limits | |
99.00% | 1 | 11.89 | 12.13 |
99.00% | 2 | 11.87 | 12.14 |
99.00% | 3 | 11.87 | 12.15 |
95.00% | 1 | 11.92 | 12.10 |
95.00% | 2 | 11.90 | 12.12 |
95.00% | 3 | 11.89 | 12.12 |
90.00% | 1 | 11.93 | 12.09 |
90.00% | 2 | 11.92 | 12.10 |
90.00% | 3 | 11.91 | 12.11 |
Prediction Interval Containing the Mean of k Future Observations |
|||
---|---|---|---|
Confidence | k | Prediction Limits | |
99.00% | 1 | 11.89 | 12.13 |
99.00% | 2 | 11.92 | 12.10 |
99.00% | 3 | 11.94 | 12.08 |
95.00% | 1 | 11.92 | 12.10 |
95.00% | 2 | 11.94 | 12.08 |
95.00% | 3 | 11.95 | 12.06 |
90.00% | 1 | 11.93 | 12.09 |
90.00% | 2 | 11.95 | 12.06 |
90.00% | 3 | 11.96 | 12.05 |
Approximate Tolerance Interval Containing At Least Proportion p of the Population | |||
---|---|---|---|
Confidence | p | Tolerance Limits | |
99.00% | 0.900 | 11.92 | 12.10 |
99.00% | 0.950 | 11.90 | 12.12 |
99.00% | 0.990 | 11.86 | 12.15 |
95.00% | 0.900 | 11.92 | 12.10 |
95.00% | 0.950 | 11.90 | 12.11 |
95.00% | 0.990 | 11.87 | 12.15 |
90.00% | 0.900 | 11.92 | 12.09 |
90.00% | 0.950 | 11.91 | 12.11 |
90.00% | 0.990 | 11.88 | 12.14 |
Confidence Limits Containing the Mean |
||
---|---|---|
Confidence | Confidence Limits | |
99.00% | 11.997 | 12.022 |
95.00% | 12.000 | 12.019 |
90.00% | 12.002 | 12.017 |
Prediction Interval Containing the Standard Deviation of k Future Observations |
|||
---|---|---|---|
Confidence | k | Prediction Limits | |
99.00% | 2 | 0.0003 | 0.1348 |
99.00% | 3 | 0.0033 | 0.1110 |
95.00% | 2 | 0.0015 | 0.1069 |
95.00% | 3 | 0.0075 | 0.0919 |
90.00% | 2 | 0.0030 | 0.0932 |
90.00% | 3 | 0.0106 | 0.0825 |
Confidence Limits Containing the Standard Deviation |
||
---|---|---|
Confidence | Confidence Limits | |
99.00% | 0.040 | 0.057 |
95.00% | 0.041 | 0.055 |
90.00% | 0.042 | 0.053 |