Key to Practice Midterm I

Problem 1
A.  The frequented supermarket is the response variable .  Examples are:  Albertson's and Raleys

B.  Qualitative, not applicable

C. South Lake Tahoe Residents

D.  The 50 employees that were questioned

E.  Extraneous factors:  Type of job, Location of work.  The study is not accurate since Raleys is the closest supermarket, workers at Horizon are more likely to shop there.

Problem 2
A.  At least 49%

B.  Change this problem to 16% chance, then the answer is $30.

Problem 3

A. 

    El            La
            |1  |0
          1|2  |2235
            |3  |35
      643|4  |466
      551|5  |11
        62|6  |2668
          4|1  |42
          2|8  |
        92|9  |
            |10|1
            |11|
          1|12|
          0|13|

  Both distributions are bimodal, but the El Nino year has a higher standard deviation.  The El Nino has two high outliers and one low outlier.  The La Nino has one high outlier.  La Nina years do not always produce less rain, however, they often do, hence we should prepare for a draught, but not be surprised if one does not happen.

Problem 4

A.  At least 89%        B.  Roughly 99.7%

Problem 5

A.  4        B.  4.5        C.  2        D.  sqrt(2) = 1.414        E.  The standard deviation would increase since that student would be far from the mean.

Problem 6

A. Done in class

B.  B and C are mutually exclusive since if Dr. Rork attends to all three then Dr. Williams cannot attend to any.

C.  None are independent, since knowing A occurs, B must occur and C is less likely to occur.  If B is known, then

Midterm I Review

Define the following terms. Compare and Contrast.  Provide an example and write down the symbol for the term if possible.

  1. Population vs.  Sample

  2. Sample Size

  3. Discrete Data, Continuous Data

  4. Qualitative Data, Quantitative Data, Boolean Data

  5. Mean, Median, Trimmed Mean, Outlier

  6. Variance and Standard Deviation

  7. Histogram vs Stem and Leaf Diagram

  8. Random Variable, Extraneous Factor, Stratified Random Sample

  9. Relative Frequency Distribution, Cumulative Relative Frequency

  10. Unimodal, Bimodal

  11. Chevychev's Rule, Empirical Rule

  12. Event, Simple Event

  13. Probability, And, Or

  14. Mutually Exclusive, Independent, Conditional Probability

  15. Expected Value, Standard Deviation of a Random Event

  16. Sampling With Replacement, Sampling Without Replacement

  17. Probability Distribution, Probability Histogram