STAT 1.1

The number of hours a group of 7 children in Mrs. Smith's kindergarten class watch televisions in a day

Population: all the children in Mrs. Smith's kindergarten class

The number of hours a group of 15 children in Mrs. Smith's kindergarten class sleep in a day

Sample

The amount of money each person in your math class spends on clothes in a month

Population

The high school GPA's of all the professors at the local college

Population

71% of all babies born at the local hospital last year were boys

Population Parameter

74% of all instructors at your school teach 2 or more classes

Population Parameter

After an airplane security scare on Christmas day, 2009, the Gallup organization interviewed 542 American air travelers about increased security measures at airports. The report stated that 78% of American air travelers are in favor of United States airports using full-body-scan imaging on airline passengers.

Population: All American air travelers Sample: The 542 American air travelers who were surveyed The value 78% refers to all American air travelers; thus this is a population Parameter. DESCRIPTIVE STATISTICS

Rasmussen Reports also conducted a survey in response to the airport security scare on Christmas day, 2009. The national telephone survey of 1000 adult Americans found that 59% of Americans surveyed favor racial profiling as a means of determining which passengers to search at airport security checkpoints.

Population: All adult Americans Sample: The 1000 adult Americans who were surveyed The value 59% refers to only those adult Americans who were surveyed, thus this is a sample Statistic. INFERENTIAL STATISTICS

In a survey, 359 college students at the University of Jackson were asked if they had tried the October flavor of the month at the campus coffee shop. Eighty-three of the students surveyed said yes.

Population: All college students at the University of Jackson Sample: The 359 college students who were surveyed

A survey of 1125 households in the United States found that 24% subscribe to satellite radio.

Population: All households in the United States Sample: The 1125 households in the United States that were surveyed

A recent poll of 1887 corporate executives showed that the average price of a corporate executive's car is $44,200

Sample Statistic

A recent poll of 3482 home owners in Pennsylvania showed that the average price of a house in the U.S is $274,000

Sample Statistic Inferential Statistic

The number of times 8 our of 36 students on your floor order Chinese in a week

Sample: 8 students on your floor

"AOL had 900 journalists, 500 of them at its local Patch news operation.... By the end of 2011, Bloomberg expects to have 150 journalists and analysts for its new Washington operation, Bloomberg Government."

When the authors identify AOL as having "had 900 journalists, 500 of them at its local Patch news operation," they are describing the actual counts, not estimates; thus these numbers of journalists are descriptive statistics. On the other hand, when the authors state "By the end of 2011, Bloomberg expects to have 150 journalists and analysts for its new Washington operation," they are referring to an estimate based on past descriptive statistics. Therefore the estimate, 150 journalists and analysts, is an inferential statistic.

Sample Statistics

are numerical descriptions of sample characteristics

Data

are the counts, measurements, or observations gathered about a specific variable in a population in order to study it

Descriptive Statistics

as a science, gathers, sorts, summarizes, and displays the data

Inferential Statistics

as a science, involves using descriptive statistics to estimate population parameters

65% of all students at the local university voted in the last election

descriptive statistic

Parameter

is a numerical description of a population characteristic

Population

is a particular group of interest

Census

is a study in which data are obtained from every member of the population

Sample

is a subset of the population from which data are collected

Variable

is a value or characteristic that changes among members of the population

The average number of hours students in your statistics class study per week is 17.4

population parameter

The final exam scores of 4 out of the 27 students in your psychology class

population: all students in your psychology class sample: 4 out of the 27 students in your psychology class