z = -1.644853 (approx).
77th percentile.
2.326
1
z = 0.5244, approx.
There is insufficient information in the question to answer it. To determine Z score, you need raw score, mean, and standard deviation. Please restate the question.
77th percentile.
75th percentile.
z = 1.281551
You need to look up z-score tables.
2.326
It is -1.281551
2.82
z = 1.28, approx.
The top percentile (> 99.86%)
1
z = 0.5244, approx.
If the Z-Score corresponds to the standard deviation, then the distribution is "normal", or Gaussian.