Problem 7-19
Supercelluar Battery Life-Reliability
Enter data only in the shaded cells
This spreadsheet is designed to calculate the probability of values equal to, or less than, a desired x value,
given the mean and standard deviation of a normally distributed variable. It uses the cumulative normal distribution
Enter the mean of the distribution in shaded cell D8 and the standard deviation in shaded cell D9. below.
Enter the desired X-value in shaded cell D10, below. The calculated z-value and probability will be seen in D11 and D12.
Mean of distribution 950 950 NORMAL PROBABILITY CALCULATIONS
Std deviation of distribution 40 40
Desired x-value 1010 900 Mean of distribution 1020
Calculated z-value 1.50 -1.25 Std Dev of distribution 20
Probability of x, or less 0.93319 0.10565 Desired x-value 1044
(X-axis) Probability Using Prob. of x, or less 0.88493
Desired x-values Equivalent – Z Values NORMS.DIST
790 -4.00 0.00003 Equivalent Probability Using Desired
794 -3.90 0.00005 Z Values NORM.DIST x-values
798 -3.80 0.00007 -4.00 0.00003 940
802 -3.70 0.00011 -3.60 0.00016 948
806 -3.60 0.00016 -3.20 0.00069 956
0.90
1.00
Cumulative Probability Function
NORMS.DIST
Mean of distribution 1020
Std Dev of distribution 20
Prob. of x, or less 0.88493
Equivalent Probability Using Desired
Z Values NORM.DIST x-values
810 -3.50 0.00023 -2.80 0.00256 964
814 -3.40 0.00034 -2.40 0.00820 972
818 -3.30 0.00048 -2.00 0.02275 980
822 -3.20 0.00069 -1.60 0.05480 988
826 -3.10 0.00097 -1.20 0.11507 996
830 -3.00 0.00135 -0.80 0.21186 1004
834 -2.90 0.00187 -0.40 0.34458 1012
838 -2.80 0.00256 0.00 0.50000 1020
842 -2.70 0.00347 0.40 0.65542 1028
846 -2.60 0.00466 0.80 0.78814 1036
850 -2.50 0.00621 1.20 0.88493 1044
854 -2.40 0.00820 1.60 0.94520 1052
858 -2.30 0.01072 2.00 0.97725 1060
862 -2.20 0.01390 2.40 0.99180 1068
866 -2.10 0.01786 2.80 0.99744 1076
870 -2.00 0.02275 3.20 0.99931 1084
874 -1.90 0.02872 3.60 0.99984 1092
878 -1.80 0.03593 4.00 0.99997 1100
882 -1.70 0.04457
886 -1.60 0.05480
890 -1.50 0.06681
-2.80 0.00256 964
-2.40 0.00820 972
-2.00 0.02275 980
-1.60 0.05480 988
-1.20 0.11507 996