STAT

Card Set Information

Author:
bettyvillagomez
ID:
78128
Filename:
STAT
Updated:
2011-04-08 13:31:02
Tags:
BEGINNING STATISTICS
Folders:

Description:
UNIT 3
Show Answers:

Home > Flashcards > Print Preview

The flashcards below were created by user bettyvillagomez on FreezingBlue Flashcards. What would you like to do?


  1. WHAT IS THE NORMAL DISTRIBUTION?
    IS A CONTINOUS PROBABILITY DISTRIBUTION FOR A GIVEN RANDOM VARIABLE, X, THAT IS COMPLETELY DEFINED BY ITS MEAN AND STANDARD DEVIATION
  2. A NORMAL DISTRIBUTION IS DEFINED BY ITS
    MEAN AND STANDARD DEVIATION
  3. NORMAL DISTRIBUTIONS ARE ALL BELL SHAPED. THE MEAN, MODE, AND MEDIUM ARE ____.
    ALL THE SAME VALUE.
  4. THE MEAN/MEDIUM/MODE IS LOCATED AT THE CENTER OF A DISTRIBUTION
    MEAN
  5. WHAT DETERMINES THE SHAPE OF THE CURVE?
    STANDARD DEVIATION
  6. WHAT IS THE STANDARD DEVIATION
    • DISTANCE FROM THE MEAN TO ONE OF THE INFLECTION POINTS
    • The standard deviation is a statistic that tells you how tightly
    • all the various examples are clustered around the mean in a set of data.
    • When the examples are pretty tightly bunched together and the
    • bell-shaped curve is steep, the standard deviation is small. When the
    • examples are spread apart and the bell curve is relatively flat, that
    • tells you you have a relatively large standard deviation.
  7. INFLECTION POINT
    IS A POINT ON THE CURVE WHERE THE CURVUTURE OF THE LINE CHANGES
  8. The inflection points are either:
    • u-o
    • u+o
  9. 3 identical bell shaped curvatures on one line all have the same ____ but different ____.
    • standard deviation
    • mean
  10. Properties of a normal distribution.
    • 1. SYMEMETRIC AND BELL-SHAPED
    • 2. COMPLETELY DEFINED BY IT'S MEAN, U, AND STANDARD DEVATION, O
    • 3. TOTAL AREA UNDER CURVE IS =1
    • 4. CURVE DOES NOT CROSS OR TOUCH X AXIS
  11. SYMBOLS U AND O
    • U - MEAN
    • O- STANDARD DEVATION
  12. Properties of a Standard Normal Distribution

    *special version of the normal distribution
    Has the same properties as the normal distribution but always has a MEAN OF 0, and a STANDARD DEVIATION of 1
  13. What kind of curve is this?
    Mean- 0
    Standard deviation- 1
    Standard Normal Distribution
  14. The larger the standard deviation, the _____ area there will be in the tail of the distribution.
    Why
    • More area
    • The curve will appear flatter
    • Because the standard deviation determines the height of the bell shaped distribution
  15. PROBABILITY CERTAINLY EQUALS
    WHY IS X<x
    • 1
    • X= THE PROBABILITY, WHICH MUST BE EQUAL OR LESS THAN 1
  16. What does the z score do?
    The z score is a formula t/f
    transforms a normal random variable into a standrard normal random variable.

    True

    Z= x-u / o
  17. HOW WOULD YOU WORD THE EQUATION OF A PROBABIILTY THAT IS BETWEEN 659-1530. WHICH WAYS ARE THE SYMBOLS FACING?
    • P (659 < X < 1530)
    • <------ TO THE LEFT
  18. THE CUMMULATIVE STANDARD NORMAL TABLE GIVES US THE ANSWERS FOR PROBABILITYS OF THE LEFT/RIGHT OF Z.
    LEFT
  19. TABLE TO LOOK UP PROBABILITIES
    CUMMULATIVE STANDARD NORMAL TABLE
  20. THE "Z VALUE" CORRESPONDS TO
    THE PROBABILITY GIVEN BY THE CHART.
  21. GIVEN: X=46.2, U=46 AND O=1.4. INDICATE WHERE ON THE CURVE THE X VALUE WOULD BE.
    • IT WOULD BE ON THE HORIZONTAL LINE, AFTER 46
    • 40.4_________46___X________51.6
  22. What does the z score do?
    The z-score (z) can transform a normal random variable into a standard normal random variable.

    • z= X-U
    • ------------
    • O

What would you like to do?

Home > Flashcards > Print Preview