Stat 135 EA275 11:30am TA: Dongmei Li
Stat 135 Friday lab section Name:
Lecture review:
1. Population: entire group of individuals about which we want information.
2. Sample: Part of population from which we actually collect information and used
to draw the conclusion about the whole.
3. Parameter: a number that describes the population. A fixed number, but we do
not know its value in practice.
4. Statistic: a number that describes a sample; its value is known when we take a
sample; It change from sample to sample; usually used to estimate an unknown
parameter.
Question:
Recently the Gallup Poll conducted a survey of American teenagers (aged 13 to 17) to
find out what percentage of them felt their schooling was doing a good job of preparing
them for the future. Out of 785 respondents, 78% felt somewhat confident or very
confident that their school was doing a good job.
Can you identify population, sample, parameter and statistic from above paragraph?
Population: American teenagers (aged 13 to 17)
Sample: 785 respondents
Parameter: percentage of American teenagers who felt their schooling was doing a good
job of preparing them for the future.
Statistic: 78% of American teenagers who felt their schooling was doing a good job of
preparing them for the future.
