edition by Jeff Bennett, William Briggs, Mario Triola
Statistics (The Science) - ANSWER:collecting, organizing, and interpreting data
Statistics (The Thing) - ANSWER:The data that describes or summarizes something.
Population - ANSWER:Complete set of people or things being studied. (This set is
usually too large to reasonably directly calculate anything.)
Population Parameter - ANSWER:specific numbers describing the specific
characteristics of the population. (You can almost never have this exact number so
we just get close enough... using statistics!)
Sample - ANSWER:Subset of the population from which data are actually obtained.
Sample Statistic - ANSWER:numbers describing characteristics of the sample found
by consolidating or summarizing the raw data
Raw Data - ANSWER:actual measurements/observations collected from sample
margin of error - ANSWER:used to calculate range of values. (Confidence Interval
defined as 95%)
confidence interval - ANSWER:the range of values within which a population
parameter is estimated to lie.
Suppose we have a sample statistic of average height of 5.25 feet at a high school.
Also, the margin of error is plus or minus .25 feet. What is the confidence interval? -
ANSWER:Confidence interval is from 5 feet to 5.5 feet. The hope is that with 95%
accuracy the actual average height of everyone at the high school is between 5 feet
and 5.5 feet.
Steps in a statistical study - ANSWER:1. Goals
2. Population
3. Study subject
4. Choose representative sample
5. Collect raw data
6. Summarize
7. Make inference about population
8. Draw conclusions (what was learned? were our goals reached?
Is this possible? After randomly selecting 1009 adults and surveying each of them, a
pollster was able to determine precisely 54% of all American adults are not
comfortable having drones make deliveries for them. - ANSWER:NOT POSSIBLE
, because the population parameter is always in a confidence interval and there is
always a margin of error.
Population: American adults
Sample: 1009 adults
Is this possible? In another country, a poll conducted two months before the
presidential election predicted that the Green Party candidate would win with 55%
of the vote: the survey had a margin of error of 3 percentage points. The Green Party
lost the election. - ANSWER:It is POSSIBLE because the Confidence Interval is only
95% accurate.
In a Pew Research Center poll of 1501 randomly selected adults in Latin America,
77% said that global warming is already harming people around the world. The
margin of error is 2% What is the population, sample, sample statistic, margin of
error, and confidence interval? - ANSWER:Population: Adults in Latin America
Sample: The 1501 selected adults
Sample Statistic: 77%
Margin of error: 2%
Confidence Interval: 75% to 79%
Define census and list pros and cons - ANSWER:the collection of data from every
member of the population.
Pros: Exact average of something
Cons: Often impractical, too $$/time-consuming
representative sample - ANSWER:a sample in which the relevant characteristics of
the sample members are generally the same as the characteristics of the population
1.1 Example 1 - Representative Sample for Heights: Suppose you want to determine
the average (mean) height of all students at your school. Which is more likely to be a
representative sample for this study: the men's basketball team or the students in
your statistics class? - ANSWER:The men's basketball team is not a representative
sample for a study of height, both because it consists only of men and because
basketball players tend to be taller than average. The mean height of the students in
your statistics class is much more likely to be close to the mean height of all
students, so the members of your class make a more representative sample than the
members of the men's basketball team.
Bias - ANSWER:when a statistical study has a design or conduct that tends to favor a
certain result.
Some ways bias can occur is - ANSWER:- Members of the sample differ in some
specific way from members of the population
- A researcher has a personal stake in a particular outcome of a study
A data set is biased if its values were collected in a way that intentionally or
unintentionally makes the data unrepresentative of the population
- A study that is done well reported in a bias fashion