# Statistics Exam 1

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1. z-score:

represents number of standard deviations a data value falls above or below the mean.

• z= (X-μ)/σ
• X= score
• μ= mean
• σ= standard deviation
2. Percentile:
divides a distribution into 100 equal parts.

Percentile= [((# of values less than X) + .5)/total # of values] * 100%
3. Outlier:
extremely high or low value in a set of data
4. Normal graph:
Bell-shaped
5. Normal Rule:
given to a normal (bell-shaped) distribution

• | | | | I | | | |
• [ 68%]
• [ 95% ]
• [ 99.7% ]
6. Stem and leaf plot:
• First digit on one side, second digit(s) on the other side.
• ex.: 18 24 25 28 39 45 46 46 49

• 1 | 8
• 2 | 4 5 8
• 3 | 9
• 4 | 5 6 6 9
7. Nominal
• No order
• ex: religion, race, hair color, gender
8. Ordinal:
• low detail order
• ex: sequels, seasons, grades, months, alphabet
9. Intervals:
• High detail oorder, 0≠ nothing
• ex: temperature, clock time, years, IQ
10. Ratio:
• high detail order, 0= nothing
• ex: height, speed, salary, age
11. Categorical:
• -class
• -frequency
• -percent
12. Ungrouped:
• -class
• -class boundaries (the x.5 numbers above and below each class)
• -frequency
• -cumulative frequency (total up to a certain point; add number from the class before)

*list classes not listed or classes in between
13. Grouped:
• -class
• -class boundaries (x.5 above and below number)
• -frequency
• -cumulative frequency (add frequency from class before)
• -relative frequency (frequency÷total from cumulative frequency)
• -cumulative relative frequency
14. Histogram:
bar graph
15. Frequency polygon:
line graph that originates from 0 before first value and ends at 0 after last value.
16. cumulative frequency graph:
line graph that originates from 0 before first value and ends with a horizontal line after last value.
17. Nominal:
ordinal:
interval:
ratio:
• mode
• median
• (symmetrical) mean; (skewed) median
• (symmetrical) mean; (skewed) median
18. Pareto chart:
bar graph used to show frequencies for nominal or qualitative variables.
19. Time series graph:
line graph used to show a pattern or trend that occurs over a period of time. Doesn't originate from 0 and ends at last value.
20. Pie graph:
used to show the relationship between the parts and the whole.
21. Mean (μ) rounding rule:
round to one more decimal place than occurs in the raw data.
22. Midrange:
average of highest and lowest value.
23. Weighted Mean:
sum of (weights*values)÷sum of weights
24. Variance:
the average of the squares of each value's distance from the mean. σ^2

• ex: (0+2+0+0+1+1+0)^2 ÷ 7
• σ^2= 6/7
25. Standard deviation:
the square root of the variance. σ
26. rounding rule for variance and standard deviation:
round to one more decimal place than occurs in raw data
27. If the word "sample" is used in description:
while doing the mean, subtract 1 from the bottom number in the division.

• ex: 0+4+0+0+1+1+0 ÷ 7-1
• variance: s^2= 6/6= 1
• std. deviation: s= 1
28. the coefficient of variation:
• CVar= (σ ÷ μ) * 100%
• μ: mean
• σ: std. deviation

When comparing two variations, the higher number is more variable.

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 Author: tenorsextets ID: 72623 Filename: Statistics Exam 1 Updated: 2011-03-13 20:52:15 Tags: Statistics Folders: Description: read title Show Answers:

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