Download USMLE Step 1 Web Prep — Descriptive Statistics 155705 >>> 00:00

USMLE Step 1 Web Prep — Descriptive Statistics
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SLIDE 1 of 13
Statistics
Descriptive Statistics
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Descriptive Statistics
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Distributions - Central tendency
Mean: average
Median: midpoint, 50th percentile
Mode: most frequent value
In a normal distribution these are the same value
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SLIDE 3 of 13
Descriptive Statistics
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
Distributions - Central tendency
Mean: average
Median: midpoint, 50th percentile
Mode: most frequent value
In a normal distribution these are the same value
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SLIDE 4 of 13
Descriptive Statistics
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Distributions - Central tendency
Mean: average
Median: midpoint, 50th percentile
Mode: most frequent value
In a normal distribution these are the same value
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Measures of Variability
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Range
Standard deviation
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Measures of Variability
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Range
Standard deviation
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SLIDE 7 of 13
Measures of Variability
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Range
Standard deviation
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Measures of Variability
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Range
Standard deviation
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Measures of Variability
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Range
Standard deviation
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Measures of Variability
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Range
Standard deviation
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Practice Questions
1. In a normal distribution curve, what percent of the cases are below 2SD below the
mean?
2. In a normal distribution curve, what percent of the cases are above 1SD below the
mean?
3. A student who scores at the 97.5 percentile falls where on the curve?
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SLIDE 12 of 13
Practice Questions
A student took 2 tests. On which test did the student do better?
Score
Mean
Standard
Deviation
Test A
45
30
5
Test B
60
40
10
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SLIDE 13 of 13