Percentile Ranks and Normal Distribution Flashcards
What is percentile?
a ordinal measurement of data compared to some norm
90th percentile means that …
the given score is higher than 90% of all scores ( The score is in the upper 10%)
25th percentile =
first quartile (Q1) = lower quartile = lowest 25% of data
50th percentile =
second quartile (Q2) = Median = cuts data set in half
75th percentile =
third quartile (Q3) = upper quartile = cuts off highest 25% of data, or lowest 75%
Standard deviation is denoted:
σ or s
Mean is denoted:
µ
What are the % of data values on a normal distribution curve?
- 0.13%
- 2.15%
- 13.59%
- 34.13%
- 34.13%
- 13.59%
- 2.15%
- 0.13%
In the normal distribution bell curve, ___ % of the data is above the mean.
50%
In the normal distribution bell curve, ___ % of the data is within one standard deviation of the mean.
68.26%
In the normal distribution bell curve, ___ % of the data is within two standard deviations of the mean.
95.44%
In the normal distribution bell curve, ___ % of the data is within three standard deviations of the mean.
99.74%
In the normal distribution bell curve, ___ % of the data is between 1 and 2 standard deviations above the mean.
13.59%
In the normal distribution bell curve, ___ % of the data is between 1 and 2 standard deviations above the mean.
13.59%
The total area under the standard normal deviation curve is _____.
1
The standard normal deviation curve extends …
infinitely to the left and right
The standard normal deviation curve is symmetrical about
- the mean
- 50% of the area under the curve is to the left of the mean and 50% is to the right
____% of the data is represented by the area under the standard normal deviation curve.
100%
The mean, median and mode are ___________ in the standard normal deviation curve.
the same value
