cores are normally distributed with a mean of 100 and a standard devaition of 15.  What IQ score corresponds to the 84th percentile?

Fifteen students were selected and asked how many hours each studied for the final exam instatistics. Their answers were recorded here: 8,6,3,0,0,5,9,2,1,3,7,10,0,3,6. Find the mean,median, mode, range, variance and standard deviation.

National park services, a bureau of the US government responsible for park management, is interested in how the scores of their park rangers today are better or worse than in the past. The cognitive test that the forest rangers take as remained the same over the last five years. Below are the scores for each year, compute the mean, median, mode, range, and standard deviation for each year. ​       ​Current Year 56, 45, 64, 75, 87, 81, 69, 81, 58, 92, 99, 95, 75, 92, 73, 83, 47, 69, 57, 74, 62, 74, 73, 100, 83   Five Years Ago 66, 78, 75, 79, 59, 74, 55, 89, 55, 79, 68, 27, 69, 95, 68, 90, 65, 79, 69, 79, 87, 86, 98, 81, 96

what is a z-score of 80%?