QTM 100 MIDTERM 1- 2 QUESTIONS AND ANSWERS
What is the field/discipline/science of statistics? - Answers - Collecting and analyzing
numerical data, particularly to infer proportions in a whole from representative samples.
What is the difference between anecdotal evidence and formal evidence? - Answers -
Anecdotal evidence is evidence supported by what your experience is or what you have
heard, formal evidence is based in science.
Name the three main components of statistics. - Answers - Design, description,
inference
What is the difference between a population and a sample? - Answers - A sample group
is taken from the population of interest. The population represents everyone of interest
in a research question, the sample is the members of the population actually
researched.
What is the difference between descriptive and inferential statistics? - Answers -
Descriptive statistics helps describe, show or summarize data in a meaningful way,
inferential statistics involves estimation of parameters and testing statistical hypotheses.
What is the difference between a statistic and a parameter? - Answers - Properties of
populations are called parameters, properties of samples are called statistics.
What is a random sample? - Answers - A sample taken from the sampling frame in such
a way that every sample being collected has a predetermined probability of being
selected.
What are the two types of categorical variable? - Answers - Dichotomous, ordinal
How are categorical variable summarized? - Answers - In a frequency table
What is shown in a frequency table? - Answers - Frequency, percent, proportion
Which graphs are appropriate for categorical variables? - Answers - Pie charts and bar
graphs
What is a dichotomous variable? - Answers - A variable that falls exclusively into one of
two independent categories.
What is an ordinal variable? - Answers - A variable that contains a natural ordering. Ex.
freshman, sophomore, junior, senior.
What are the two types of quantitative variable? - Answers - Continuous, discrete
, Name the 7 main descriptive terms for distribution shape. - Answers - Unimodal,
bimodal, left-skewed, right-skewed, symmetric, bell-shaped, uniform
What are the measures of center? - Answers - Mean, median, mode
What are the measures of spread? - Answers - Standard deviation, variance, range,
IQR
What are the measures of position? - Answers - Quartiles, percentiles
Which measures of center and spread are good at/bad at resisting outliers? - Answers -
The IQR is resistant to outliers, so is the mode. The mean, standard deviation and
range are not resistant.
Properties of standard deviation - Answers - 1. Used only to measure spread of a data
set
2. Is never negative
3. Sensitive to outliers
4. Directly proportional to spread
The Empirical Rule - Answers - In a normal distribution, 68% of data will fall within one
standard deviation of the mean, 95% will fall within 2 standard deviations, 98% within 3
standard deviations.
How do you construct
a) dot plots
b) histograms
c) time series
d) box plots - Answers - a) Each value in the data set is represented by a dot, values
are plotted along the X axis, and number of dots represents frequency. Good for small
data sets.
b) Gives a general idea of data using bars, good for large data sets and identifying
trends, but not for finding specific values.
c)The x axis represents time increments and the y axis represents the measured
variable
d) Use a "box" to show the IQR with a line to represent the mean and "whiskers" to
represent outliers.
What IQR range suggests an outlier? - Answers - Q1-1.5(IQR) and Q3+1.51(IQR)
How do you calculate z score? - Answers - z=observation-mean/standard deviation
What are identifiers of a bad graph? - Answers - A strange or uneven scale, unlabeled
axes, disproportionate portrayal,spread or sizing of data
What is the field/discipline/science of statistics? - Answers - Collecting and analyzing
numerical data, particularly to infer proportions in a whole from representative samples.
What is the difference between anecdotal evidence and formal evidence? - Answers -
Anecdotal evidence is evidence supported by what your experience is or what you have
heard, formal evidence is based in science.
Name the three main components of statistics. - Answers - Design, description,
inference
What is the difference between a population and a sample? - Answers - A sample group
is taken from the population of interest. The population represents everyone of interest
in a research question, the sample is the members of the population actually
researched.
What is the difference between descriptive and inferential statistics? - Answers -
Descriptive statistics helps describe, show or summarize data in a meaningful way,
inferential statistics involves estimation of parameters and testing statistical hypotheses.
What is the difference between a statistic and a parameter? - Answers - Properties of
populations are called parameters, properties of samples are called statistics.
What is a random sample? - Answers - A sample taken from the sampling frame in such
a way that every sample being collected has a predetermined probability of being
selected.
What are the two types of categorical variable? - Answers - Dichotomous, ordinal
How are categorical variable summarized? - Answers - In a frequency table
What is shown in a frequency table? - Answers - Frequency, percent, proportion
Which graphs are appropriate for categorical variables? - Answers - Pie charts and bar
graphs
What is a dichotomous variable? - Answers - A variable that falls exclusively into one of
two independent categories.
What is an ordinal variable? - Answers - A variable that contains a natural ordering. Ex.
freshman, sophomore, junior, senior.
What are the two types of quantitative variable? - Answers - Continuous, discrete
, Name the 7 main descriptive terms for distribution shape. - Answers - Unimodal,
bimodal, left-skewed, right-skewed, symmetric, bell-shaped, uniform
What are the measures of center? - Answers - Mean, median, mode
What are the measures of spread? - Answers - Standard deviation, variance, range,
IQR
What are the measures of position? - Answers - Quartiles, percentiles
Which measures of center and spread are good at/bad at resisting outliers? - Answers -
The IQR is resistant to outliers, so is the mode. The mean, standard deviation and
range are not resistant.
Properties of standard deviation - Answers - 1. Used only to measure spread of a data
set
2. Is never negative
3. Sensitive to outliers
4. Directly proportional to spread
The Empirical Rule - Answers - In a normal distribution, 68% of data will fall within one
standard deviation of the mean, 95% will fall within 2 standard deviations, 98% within 3
standard deviations.
How do you construct
a) dot plots
b) histograms
c) time series
d) box plots - Answers - a) Each value in the data set is represented by a dot, values
are plotted along the X axis, and number of dots represents frequency. Good for small
data sets.
b) Gives a general idea of data using bars, good for large data sets and identifying
trends, but not for finding specific values.
c)The x axis represents time increments and the y axis represents the measured
variable
d) Use a "box" to show the IQR with a line to represent the mean and "whiskers" to
represent outliers.
What IQR range suggests an outlier? - Answers - Q1-1.5(IQR) and Q3+1.51(IQR)
How do you calculate z score? - Answers - z=observation-mean/standard deviation
What are identifiers of a bad graph? - Answers - A strange or uneven scale, unlabeled
axes, disproportionate portrayal,spread or sizing of data
