Broadtred Tire Co.
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.
Part a Part b Part d
Mean of distribution 50000 50000 z = -1.2816 NORMAL PROBABILITY CALCULATIONS
Calculated z-value 1.20
(X-axis) Probability Using Prob. of x, or less 0.88493
Desired x-values
Equivalent – Z Values
NORM.DIST
40000 -4.00 0.00003 Equivalent Probability Using Desired
40250 -3.90 0.00005 Z Values NORM.DIST x-values
40500 -3.80 0.00007 -4.00 0.00003 940
40750 -3.70 0.00011 -3.60 0.00016 948
41000 -3.60 0.00016 -3.20 0.00069 956
41250 -3.50 0.00023 -2.80 0.00256 964
41500 -3.40 0.00034 -2.40 0.00820 972
45000 -2.00 0.02275 3.20 0.99931 1084
45250 -1.90 0.02872 3.60 0.99984 1092
45500 -1.80 0.03593 4.00 0.99997 1100
45750 -1.70 0.04457
46000 -1.60 0.05480
46250 -1.50 0.06681
46500 -1.40 0.08076
46750 -1.30 0.09680
47000 -1.20 0.11507
47250 -1.10 0.13567
50000 0.00 0.50000
50250 0.10 0.53983
50500 0.20 0.57926
50750 0.30 0.61791
51000 0.40 0.65542
51250 0.50 0.69146
51500 0.60 0.72575
0.70
0.80
0.90
1.00
Cumulative Probability Function
Calculated z-value 1.20
Prob. of x, or less 0.88493
Equivalent Probability Using Desired
Z Values NORM.DIST x-values
-4.00 0.00003 940
-3.60 0.00016 948
-3.20 0.00069 956
-2.80 0.00256 964
-2.40 0.00820 972
2.80 0.99744 1076
3.20 0.99931 1084
3.60 0.99984 1092
4.00 0.99997 1100
Mean of distribution 1020
Std Dev of distribution 20
Desired x-value 1044
51750 0.70 0.75804
52000 0.80 0.78814
52250 0.90 0.81594
52500 1.00 0.84134
52750 1.10 0.86433
53000 1.20 0.88493
58000 3.20 0.99931
58250 3.30 0.99952
58500 3.40 0.99966
58750 3.50 0.99977
59000 3.60 0.99984
59250 3.70 0.99989
59500 3.80 0.99993
59750 3.90 0.99995
60000 4.00 0.99997