Statistics Ch. 1-3
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what is population?
collection of all outcomes, responses, counts, and measurements that are of interest
what is a sample?
a subset, part of a population
what is parameter?
number description for population
what is statistic? (not statisticS)
a number description for a sample
Describe Descriptive Statistics
branch of statisticS that has organization, summary, and display of data
no conclusions are drawn
Describe inferential statistics
part of statisticS that has conclusions drawn based on a given data
give an example of parameter
In a survey of 2000 people
give an example of statistic
in a survey 20 out of 2000 people
give an example of descriptive statistics
for unmarried men, 70% were alive at age 65
give an example of inferential statistics
for married men 90% were alive at 65
....being married prolongs your life
what is qualitative data?
attributes, labels, or non-numbered entries
what is quantitative data?
consists of numerical measurement or counts
Is nominal level of measurement the lowest?
describe nominal level of measurement
- category of names, labels, qualities
- no math can be used
at what number level is the ordinal level of measurement?
describe ordinal level of measurement
- qualitative or quantitative
- data can be arranged in order but it does not matter
what level is the interval level of measurement?
3...after nominal and ordinal
what is the acronym for the level of measurement?
describe interval level of measurement
- entries can be ordered
- meaningful differences for data entries can use math
- *zero means a position on a scale*
- zero is not an inherent zero meaning doesn't mean NONE
what level is the ration level of measurement?
describe ratio level of measurement
- similar to interval level
- can use math
- zero means NONE..."inherent zero"
- a ratio from data can be made so it can be a expressed as a *multiple* of another
describe what a frequency histogram is
- a BAR graph that represents the FREQUENCY distribution of a data set:
- x-axis is quantitative and measures the data values
- y-axis measures the FREQUENCY
- BARS MUST TOUCH
describe what a frequency polygon graph is
a LINE graph that explains the continuous change in frequencies for FREQUENCY HISTOGRAM
Describe 6 methods of data collection
- 1. identify variables
- 2. make a detailed plan for collecting data
- 3. collect data
- 4. describe data using stats. techniques
- 5. interpret data
- 6. identify errors
what is observational study?
researcher observes and measures characteristics of interest
what is experiment?
a treatment is applied to part of a population and responses are observed
what is simulation?
- use math or physical model to make the conditions of a simulation or process
- INVOLVES COMPUTERS
What is Survey?
- an investigation of one or more characteristics of a population
- mostly done by interviews and mail or phone
Describe elements of experimental design: Control
for effects other than one being observed
what is confounding variables?
when an experimenter can't tell the difference between the effects or different factors on a variable
what is placebo effect?
when a subject reacts positively to a treatment when there's actually no medical treatment..."all in the head"
what is blinding?
subject doesn't know if he/she receives a treatment or placebo
what is double-blinding?
- when the experimenter or subject knows if the subject is receiving a treatment or a placebo..
- usually has a third-party involve
what is Randomization?
randomly assigning subjects to different treatment groups
what is completely randomized design?
subjects are assigned to different treatment groups through random selection
what i randomized block design?
- divide subjects with similar characteristics into blocks
- in each block, randomly assign subject into treatment groups
what is matched pairs design?
- subjects are paired according to similarity. One subject in the pair is randomly picked to receive one treatment while the other receives a different treatment
- *like twins experiment*
what is replication?
*repetition* of experiment using a large group of subjects
What is Simple Random Sample?
every possible sample of same size has same chance of being picked
what is stratefied sample?
divide population into groups and pick randomly from each group
give an example of stratefied sample
- divide by social economic level and pick households from each level
- LIKE BLOCK DESIGN EXPERIMENT
Describe Cluster Sample and give example
divide population in groups and pick all members in/or more, but not all of the clusters
example: everyone in class MTH 222 takes survey
What is systematic Sample? and give example?
choose a starting value at random the choose kth member of population
example: line up everyone and then pick every 3rd person
what is convenience?
most common by just asking...maybe for fun
what is frequency distribution?
a table shows classes or intervals of data with a count of number of entries in each class
what is range?
the difference between maximum and minimum number
what is class width?
distance from lower or upper limits of consecutive classes
what is a dot plot graph?
plotting dots into graph horizontally
what is a pie chart?
circle graph that depicts angles and percentages
what is a pareto chart graph?
separated bar graph that has the highest category to the left and NOT CONTINOUS
what is a scatter plot?
random scattering of points
what is a time series chart?
- quantitative entries for a specific amount of time
- same as line graph and scatter plot
- *x-axis is a time unit*
what is probability experiment?
action, trial, which specific results are obtained(counts, measurements, or responses)
what is an outcome?
result of a SINGLE trial
what is a sample?
- a set of all possible outcomes
- outcome is a subset of sample
what is an event?
- having one or more outcomes
- also a subset of sample
what is simple event?
consists of a SINGLE outcome event
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