MATH9C Flashcards
is a way of getting information from
data.
Statistics
Facts,
especially numerical
facts, collected
together for
reference or
information
Data
Knowledge
communicated
concerning some
particular fact.
Information
is a tool for creating new understanding from data
Statistics
Two Ways to Do Statistics
Inferential statistics and Descriptive statistics
methods of organizing, summarizing,
and presenting data in a convenient and informative way. These
methods include graphical summaries and numerical
techniques.
Descriptive statistics
methods used to make conclusions or
inferences concerning some unknown aspect of a population
based on data from a sample. Statistical inference is the process
of making an estimate, prediction, or decision about a population
based on a sample.
Inferential statistics
collection of all
possible individuals,
objects, or
measurements of
interest;
population
is a
numerical
measurement
describing some
characteristic of a
population.
parameter
a portion, or part, of the population
of interest
sample
a numerical
measurement describing some characteristic
of a sample.
Statistic
Two branches of statistics
Descriptive statistics and Inferential statistics
Survey
Collect data
Tables and graphs
Present data
Sample mean
Summarize data
Estimate the population
mean weight using the sample
mean weight
Estimation
Test the claim that the
population mean weight is 120
pounds
Hypothesis testing
the process of drawing conclusions or
making decisions about a population based on
sample results
Inference
the collection of all items of interest or
under investigation
population
an observed subset of the population
sample
a specific characteristic of a population
parameter
a specific characteristic of a sample
statistic
Values calculated using
population data are called
parameters
Values computed from
sample data are called
statistics
a procedure in which
◼ each member of the population is chosen strictly by
chance,
◼ each member of the population is equally likely to be
chosen,
and
◼ every possible sample of n objects is equally likely to
be chosen
Simple random sampling
The resulting sample is called
random sample
Greek letter sigma, indicates a sum
and is referred as a summation operation
∑
is referred to as the index of
summation or summation variable
i
the i
th term of the sum
xi
lower and upper limits of the
summation, respectively
1, n
a table that shows classes or
intervals of data with a count of the number in each class.
The frequency f of a class is the number of data points in
the class
frequency distribution
the distance between lower (or upper)
limits of consecutive classes.
class width
the difference between the maximum and
minimum data entries
range
a class is the sum of the lower and upper
limits of the class divided by two. The midpoint is
sometimes called the class mark
midpoint
a class is the portion or
percentage of the data that falls in that class. To find the
relative frequency of a class, divide the frequency f by the
sample size n
relative frequency
a class is the sum of the
frequency for that class and all the previous classes.
cumulative frequency
a bar graph that represents
the frequency distribution of a data set.
frequency histogram
the numbers that separate the
classes without forming gaps between them
Class boundaries
a line graph that emphasizes the
continuous change in frequencies.
frequency polygon
the same shape and
the same horizontal scale as the corresponding frequency
histogram.
relative frequency histogram
Measure of central tendency provides a very convenient
way of describing a set of scores with a single number that
describes the_______of the group
PERFORMANCE
It is also defined as a single value that is used to
describe the______of the data
center
There are three commonly used measures of central
tendency
MEAN
▪ MEDIAN
▪ MODE
MEAN
It is the most commonly used measure of the center of
data
▪ It is also referred as the____
arithmetic average
the data or scores that are arranged in a
frequency distribution
Grouped data
the arrangement of scores
according to category of classes including thefrequency
Frequency distribution
the number of observations falling in a category
Frequency
One formula in solving the mean for grouped data is called
midpoint method.
Median is what divides the scores in the
distribution into two equal parts.
• Fifty percent (50%) lies below the median
value and 50% lies above the median
value.
• It is also known as the______or the
50th percentile.
middle score
When the _____ value is desired.
typical
