Download Chapter 2 Review

AP Statistics
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Chapter 2 Review
Outcomes:
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Describe and apply the 68-95-99.7 rule
Describe the standard Normal Distribution
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Measure position using percentiles
Interpret cumulative relative frequency
graphs
Measure position using z-scores
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Perform Normal distribution calculations
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Transform data
Define and describe density curves
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Assess Normality
Question 1-3: 98 women and 225 men participated in a 5k road race. Below are the summary statistics from their times:
1. Santiago finished in 51st place among the men, with a time of 20.9 minutes. Keisha finished 33rd among women,
with a time of 25.2 minutes. Use percentiles and z-scores to compare Santiago’s and Keisha’s relative standing
among men and women respectively.
2. Suppose the timers of the race discovered that they accidentally started the clock 15 seconds before the race
actually started so that each racer’s finish time should be 15 seconds less. Describe the impact this would have on
the mean, median, standard deviation, and interquartile range.
3. Use the information from the computer output to sketch a possible density curve for the finish times of women in
this race. Be sure to provide a scale and label for the horizontal axis.
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4. The cumulative relative frequency graph shows the distribution of length (in cm) of fingerlings at a fish hatchery.
Determine the interquartile for this distribution.
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5. The distribution of Iowa Test of Basic Skills (ITBS) vocabulary scores for 7 grade students in Gary, Indiana, is
close to Normal. Suppose the distribution is N(6.84, 1.55).
a) Sketch the Normal density curve for this distribution. Show the standard deviation boundaries for the curve.
b) What percent of ITBS vocabulary scores are less than 3.74?
c) What percentage of scores are between 5.29 and 9.94?
d) What percentage of students scored are between 5 and 7?
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e) Calculate the z-score corresponding to a test score of 8, what does this mean?
f) What test score defines the 90th percentile?
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