Stats Test 1

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Stats Test 1
2012-06-05 19:52:42
Stats Test

Note Cars for Stats Test 1
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  1. What is an element?
    The entites on which data are collected

    EX: Name on the cities in data
  2. What is a variable?
    A characteristic of interest for the elements

    EX: Hi, Lo, Condition
  3. What is an obersvation?
    The set of measurements obtained for a particular element
  4. Data Values=
    # of variables X # of elements
  5. Ordinal
    The data have the properties of nominal data and the order or rank of the data is meangful

    A nonnumeric label or numeric code may be used

    EX: Freshmen(1), Sophomore(2), Junior(3), or Senior(4)
  6. Nominal
    Data are LABES OR NAMES used to identify an attribute of the element

    A nonnumeric label or numeric code may be used
  7. Interval
    The data have the properties of ordinal data, and the interval between observations is expressed in terms of a fixed unit of measure

    Melissa scored an 1885, Kevin scored a 1780, Melissa scored 105 points better than Kevin
  8. Ratio
    The data have all the properties of interval data and the ratio of two is meaningful

    Variables such as distance, height, weight, and time
  9. Categorical Data (Qualitative Data)
    Labels or names used to identify an attribute of each element
  10. Quantitative Data
    • Data indicating how many or how much
    • - Discrete- measuring how many
    • - Continous- measuring how much

    Always numeric
  11. Observational Studies-
    No attempt to control or influence the variables of interest
  12. Experimental Studies-
    Variables of interest of identified at different times, so they can see how each influences the outcome
  13. Frequency Distribution-
    A tabular summary of data showing the frequency of items in each of several non-overlapping classes
  14. Relative Frequency
    Frequency / total sample size
  15. Clas Width=
    Largest Data Value - Smallest Data Value / Number of Classes
  16. Skewed Right
    Longer tail to the right

    Mean will be more than the median
  17. Skewed Left
    Longer tail to the left

    Mean will be less than the median
  18. Means
    Sample mean =

    Population mean=
  19. Trimmed mean
    Deleting a % of the smallest and largest values from a data set and then computing the mean of the reamaining values
  20. Percentile formula
    i= (p/100)n

    • p= percentile
    • n= sample size
  21. Range=
    Largest value - smallest value
  22. Interquartile Range (IQR)
  23. The variance?
    The average of the squared differences b/t each data value and the mean
  24. Standard Deviation?
    The positive square root of the variance
  25. Correlation Coefficient
    Can take on values between -1 and +1

    The closer it is to 0, the weaker the relationship
  26. Arthimetic operations are inappropiate for..
    the nominal scale
  27. Statistical studes in which researchers do not control variables of interest are..
    observational studies
  28. Gender is an example of _____ data..
  29. The measure of lovation which is the most likely to be influenced by extreme values n the data set is..
  30. What is a measure of dispersion?
    Interquartile range (IQR)
  31. The descriptive measure of dispersion that is based on the concept of a deviation about the mean is?
    The standard deviation
  32. The numberical value of the standard deviation can never be..
  33. The measure of dispersion which is not measured in the same units as the original data is the..
  34. A numerical measure of linear association b/t two variables is the..
  35. The coefficient of correlation..
    cannot be larger than 1
  36. Data collected over several time periods are..
    Time series data