Parking Investigation
Inferences with Population Success Rate
Worksheet 22
Revised 2/21/03

Purpose:   Collect data
                    Estimate the proportion of parking spaces that are empty, used illegally,
                            or used poorly
                    Estimate the proportion of NC cars that have late inspection stickers and
                            the average number of months late

Data Collection:

Check each of your randomly selected (non-handicapped) parking spaces in the Forsyth lot
for the following information:

"Empty" column  Make a check in the "Empty" column if a space is empty.  If the space is
                             empty move to your next space (row on your data sheet) and continue.

"Illegal" column    Make a check for illegal parking on the "space" row for an incorrectly
                              parked car.  Cars with no sticker or a sticker that is _____________
                              would be illegally parked in Forsyth lot, unless there is a handicapped
                              placard  visible or a permission sticker from the clinic. Cars with a visitor
                              sticker on the dash or a sticker that is purple are legally parked. If you
                              find something else, please make a note and bring it back for  discussion.

"Poor" column     Check the "Poor" column if a car parked over the line for its space.

"NC" column       Check the "NC" if the car is from NC--determined by its license plate.
                             The next two columns of data only apply to NC cars.  Leave other cells
                              blank.

"Late" column     Make a check in the "Late" column for a NC car whose inspection
                             sticker has expired.  If the car is not a NC car, leave the "# Months Late"
                             column blank and proceed to the next space on your list.

"# Months Late" column    Determine the number of months that the inspection sticker is late.
                                             If sticker is not late, the "# Months Late" value is 0.  If sticker is for
                                             March, month 3, and if it is June today, month 6, then the sticker
                                             is 3 months late.

At the bottom of each column record the n value for the sample of data that you have collected
for a particular question.   For the "Empty, " "Illegal," and "Poor," columns, n=30, because you
must check each of your 30 spaces.  The population will be spaces available in the Forsyth
lot.  For the "Late" and "# Months Late" columns, n will be the number of parked NC cars for
which you determine a "# Months Late" value.

Return to class after you collect your data for computations and bonus credit.

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