Question 77:

Asked on January 22, 2008

1

Answer:

No answer provided yet.Since the data is "unnormal" you'll need to transform it to something that is closer to normality, often a log-transformation(log each value). Once the data is normal, the mean will be approximately the center (50%) and the 95th percentile is approximately 1.65standard deviations above the mean (i'm using the 1-sided area here since you said the probability the seizure will last longer). Just add 1.65 times the standard deviation to the mean to see what the cut-off value is in your data.

See the Percentile to Z-Score calculator for looking up z-score from areas or percentages.