It is -1.281551
z = 1.281551
between 15 and 20.
You need to look up z-score tables.
The top percentile (> 99.86%)
88.49% 430-400 =30 30/25 = 1.2 Z score pf 1.2 = .8849
2.326
z = 1.281551
To find what z-score represents the 80th percentile, simply solve for 0.8 = F(z), where F(x) is the standard normal cumulative distribution function. Solving gives us: z = 0.842
Right around -1.28
between 15 and 20.
77th percentile.
75th percentile.
z = -1.644853 (approx).
You need to look up z-score tables.
The top percentile (> 99.86%)
z = 0.5244, approx.
it doesn't exist.