The goal of statistics is to collect,
organize and interpret data. One important goal of statistics is making
inference about some characteristic of a population based on the information
in a sample.
For each statistics problem one should answer the following questions:
1) Who is collecting the data? I call this person or group of people, the sample collector.
2) What objects are of interest to the sample collector? These objects are measured to obtain the data set.
The set of objects actually chosen is called the sample.
4) What does the sample collector
plan to do with the data she/he will collect? The sample collector
usually has a question about the population which she/he wants to answer.
DATA SETS
Number 1 Number
2 Number 3
Number 4
12.3
202 2.12
sedan
13.5
310 2.15
station wagon
15.4
432 4.24
van
16.8
544 2.18
sedan
14.2
217 3.56
sports car
13.5
875 2.44
hatchback
12.2
344 2.37
sports car
14.6
532 3.23
van
15.7
666 3.75
coupe
15.1
443 2.12
hatchback
13.0
500 2.68
sedan
12.1
427 3.42
station wagon
13.2
763 3.61
coupe
14.5
654 4.32
hatchback
14.4
802 4.12
van
Answer each of the questions above for the examples below.
I. The Environmental Protection Agency
(EPA) performs gasoline mileage tests on new automobiles to determine the
average mileage per gallon for a particular model of automobile. In one
recent test, the EPA selected 20 new automobiles of this particular model.
The number of miles per gallon for each car was recorded after completing
a standard testing procedure.
II. At the ticket gates at many airports
across the country is posted the following notice: "Due to deliberate overbooking
of flights, there may not be a seat available for everyone who has a ticket...."
Because of the revenue due to "no-shows" (those who hold a reservation
but fail to appear for the flight and do not notify the airline in advance),
it is a common practice among airlines to overbook certain flights intentionally.
To determine how many reservations
should be taken for an Atlanta-to-Houston flight, an airline wishes to
develop a reliable estimate of the percentage of no-show for this flight.
The records of 30 Atlanta-to-Houston flights were selected at random and
the the percent of passengers with reservations who failed to show for
the flight was recorded for each.