STAT 330 Exam 1 with Complete
Solutions
The science of collecting, organizing, summarizing, and analyzing information to draw
conclusions or answer questions. - ANSWER-Statistics
Procedures used for summary and description of data. - ANSWER-descriptive statistics
Procedures used to draw conclusions about the entire population based on the sample.
- ANSWER-Inferential Statistics
A set of all measurements of interest to the investigator. - ANSWER-Population
A subset of measurements selected from the population of interest. - ANSWER-Sample
A numerical summary of a population. - ANSWER-Parameter
A numerical summary of a sample. - ANSWER-Statistic
A characteristic that changes or varies over time and/or for different individuals or
objects under consideration. - ANSWER-Variable
Value that is determined by chance. - ANSWER-Random Variable
Individual or object on which a variable is measured. - ANSWER-Experimental unit
The difference between a sample result and the true population result. - ANSWER-
Sampling error
Measures a quality or characteristic of an individual. - ANSWER-Qualitative Variable
Measures a numerical quantity of an individual. - ANSWER-Quantitative Variable
Values are finite or countable. Cannot take on every possible value between any two
possible values. - ANSWER-Discrete Variable
Can assume infinitely many values corresponding to points on a number line -
ANSWER-Continuous Variable
Each member of the population has an equal chance of being selected - ANSWER-
Random Sample
, 3 tools to present data? - ANSWER-frequency table, histogram, stem and leaf plot
lists categories (or classes), along with counts (or frequencies) of the number of
observations that fall into each category - ANSWER-frequency table
Guidelines for number of classes in a frequency tables - ANSWER-sample size 25 => 6
classes
sample size 50 => 7 classes
sample size 100 => 8 classes
sample size 200 => 9 classes
sample size 500 => 10 classes
guidelines for width of a frequency table - ANSWER-whenever feasible all classes must
be of the same width.
all observations must belong to one and only one class
determining class width equation for frequencies tables - ANSWER-class width =
range/number of classes
round result up to the next whole number
if the number of classes divided into the range evenly with no remainder you will need to
add another class for all of the data to be included
determining range equation - ANSWER-range = highest observation - lowest
observation
how to set up classes for frequency tables - ANSWER-set the lowest observation as the
lower limit if the first class
add the class width to the lower limit of the first class to get the lower limit of the second
class and so on until you get the desired number of classes
summary of steps of how to set up a frequency table - ANSWER-step 1: determine
number of classes
step 2: determine class width
step 3: set up lower class limits
step 4: set upper class limits
step 5: tally observations
of a class is the sum of the frequency of that class and all previous classes - ANSWER-
cumulative frequency
of a class is the proportion of observations/scores that fall in that class - ANSWER-
relative frequency
equation to find the relative frequency - ANSWER-relative frequency = class
frequency/sum of all frequencies
Solutions
The science of collecting, organizing, summarizing, and analyzing information to draw
conclusions or answer questions. - ANSWER-Statistics
Procedures used for summary and description of data. - ANSWER-descriptive statistics
Procedures used to draw conclusions about the entire population based on the sample.
- ANSWER-Inferential Statistics
A set of all measurements of interest to the investigator. - ANSWER-Population
A subset of measurements selected from the population of interest. - ANSWER-Sample
A numerical summary of a population. - ANSWER-Parameter
A numerical summary of a sample. - ANSWER-Statistic
A characteristic that changes or varies over time and/or for different individuals or
objects under consideration. - ANSWER-Variable
Value that is determined by chance. - ANSWER-Random Variable
Individual or object on which a variable is measured. - ANSWER-Experimental unit
The difference between a sample result and the true population result. - ANSWER-
Sampling error
Measures a quality or characteristic of an individual. - ANSWER-Qualitative Variable
Measures a numerical quantity of an individual. - ANSWER-Quantitative Variable
Values are finite or countable. Cannot take on every possible value between any two
possible values. - ANSWER-Discrete Variable
Can assume infinitely many values corresponding to points on a number line -
ANSWER-Continuous Variable
Each member of the population has an equal chance of being selected - ANSWER-
Random Sample
, 3 tools to present data? - ANSWER-frequency table, histogram, stem and leaf plot
lists categories (or classes), along with counts (or frequencies) of the number of
observations that fall into each category - ANSWER-frequency table
Guidelines for number of classes in a frequency tables - ANSWER-sample size 25 => 6
classes
sample size 50 => 7 classes
sample size 100 => 8 classes
sample size 200 => 9 classes
sample size 500 => 10 classes
guidelines for width of a frequency table - ANSWER-whenever feasible all classes must
be of the same width.
all observations must belong to one and only one class
determining class width equation for frequencies tables - ANSWER-class width =
range/number of classes
round result up to the next whole number
if the number of classes divided into the range evenly with no remainder you will need to
add another class for all of the data to be included
determining range equation - ANSWER-range = highest observation - lowest
observation
how to set up classes for frequency tables - ANSWER-set the lowest observation as the
lower limit if the first class
add the class width to the lower limit of the first class to get the lower limit of the second
class and so on until you get the desired number of classes
summary of steps of how to set up a frequency table - ANSWER-step 1: determine
number of classes
step 2: determine class width
step 3: set up lower class limits
step 4: set upper class limits
step 5: tally observations
of a class is the sum of the frequency of that class and all previous classes - ANSWER-
cumulative frequency
of a class is the proportion of observations/scores that fall in that class - ANSWER-
relative frequency
equation to find the relative frequency - ANSWER-relative frequency = class
frequency/sum of all frequencies
