They were reasonably accurate she ultimately won the national popular vote by 2.1 percentage points. Using the standard normal table, the total probability to the right of z2.18 and to the left of z1.75 is. The Standard Deviation of 1. In Rating 'B', even though the group mean is the same (3.0) as the first distribution, the Standard Deviation is higher. The national polls indicated, on average, that Clinton would win the national popular vote by about 3 percentage points. Each piece was weighed on very accurate scale. The individual responses did not deviate at all from the mean. A table is then used to determine a multiplier to use along with the standard deviation to determine ranges of numbers which would account for a specified percentage of the occurrences. The national polls were generally correct and accurate by historical standards. The NORM.S.DIST function can be used to determine the probability that a random variable that is standard normally distributed would be less than 0. It will calculate the Excel Standard Normal Distribution function for a given value. It seems like not having the value in your table would be a problem, but it's a very small one $-$ since your answer for $P(01$ and $Z< -1$), the integral will be bounded below by the midpoint rule and above by the trapezoidal rule, which usefully bounds where the answer can lieīut, really, just using the limits provided by 3 and $\infty$ is plenty, I imagine. The statistical model uses the standard deviation calculation to describe the probability of a number occurring in reference to the mean in a normal distribution. The NORM.S.DIST Function is categorized under Excel Statistical functions. Your question should therefore be modified to ask "*How do I deal with the fact that my table doesn't go as high as my $Z$ value?*" Your problem appears to be that your table doesn't go further. The standard normal ranges from $-\infty$ to $\infty$.