Answer:
Z = 1.095.
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
What is the Z-score that corresponds to the top 13.7% (or the 86.3-th percentile) of the standard normal distribution?
Looking at the z-table, it is Z when it has a pvalue of 0.863, which is between 1.09 and 1.10, so it is Z = 1.095.