Introduction to Plan Making and Implementation Flashcards
Plan making is a three-part process, according to The Practice of Local Government Planning
- Goals and visions;
- Analysis of current problems; and
- Creation and evaluation of alternatives.
survey
Research method that allows one to collect data on a topic that cannot be directly observed, such as opinions on downtown retailing opportunities.
sampling frame
Population of interest
cross-sectional
Gathers information about a population at a single point in time. For example, planners might conduct a survey on how parents feel about the quality of recreation facilities as of today.
longitudinal surveys
Some cities conduct a citizen survey of service satisfaction every couple of years. This data can be combined to compare the differences in satisfaction between 1995 and 2005.
Written surveys
Mailed, printed in a newspaper, or administered in a group setting. Written surveys are very popular when a planner is trying to obtain information from a broad audience, such as general opinions about the community.
Group-administered surveys
Appropriate when there is a specific population that a planner is trying to target. example would be to survey participants in recreation programming by asking each person to complete a survey at the end of class.
Drop-off survey
The survey to be dropped off at someone’s residence or business.
Oral surveys
Administered on the phone or in person.
Phone surveys
Useful when you need yes/no answers.
Online surveys
These can be administered on a website, e-mail, or text message.
sample design
The sample should represent the population about which information is being gathered.
probability sampling
There is a direct mathematical relation between the sample and the population, so that precise conclusions can be drawn.
random samples
Where everyone has the same chance of being selected to participate in the survey
stratified samples
The population is divided into separate groups or classes, from which a sample is drawn such that the classes in the population are represented by the classes in the sample
cluster samples
Special form of stratified sampling, where a specific target group out of the general population is sampled from, such as the elderly, or residents of a specific neighborhood.
non-probability sampling
There is no precise connection between the sample and the population, so that the results have to be interpreted with caution since they are not necessarily representative of the population.
convenience sample
Individuals that are readily available
snowball sample
Where one interviewed person suggests other potential interviewees
volunteer sample
Consists of self-selected respondents
volunteered geographic information
When participants enter information on a web map
Types of non-probability sampling
convenience sample
snowball sample
volunteer sample
volunteered geographic information
Types of probability sampling
random samples
systematic samples
stratified samples
cluster samples
three important steps in the statistical process
1) collect data
2) describe and summarize
3) interpret
Types of measurement
Nominal data
Ordinal data
Interval data
Ratio data
Nominal data
Classified into mutually exclusive groups or categories and lack intrinsic order. A zoning classification, social security number, and sex are examples of nominal data.
Ordinal data
Ordered categories implying a ranking of the observations. Examples of ordinal data are letter grades, suitability for development, and response scales on a survey
Interval data
Data that has an ordered relationship where the difference between the scales has a meaningful interpretation. Example of interval data is temperature. difference between 40 and 30 degrees is the same as between 30 and 20 degrees, but 20 degrees is not twice as cold as 40 degrees.
Ratio data
Gold standard of measurement, where both absolute and relative differences have a meaning. Example of ratio data is a distance measure, where the difference between 40 and 30 miles is the same as the difference between 30 and 20 miles, and in addition, 40 miles is twice as far as 20 miles.
Types of Variables
Quantitative variables
Qualitative variables
Continuous variables
Discrete variables
variable
Mathematical representation of a concept, and thus also of the measurement of that concept
quantitative variables
The actual numerical value is meaningful. Examples are household income, level of a pollutant in a river. Quantitative variables represent an interval or ratio measurement
qualitative variables
the actual numerical value does not have meaning. Example is zoning classification. Qualitative variables correspond to nominal or ordinal measurement.
Continuous variables
Take an infinite number of values, both positive and negative, and with as fine a degree of precision as desired.
Discrete variables
Only take on a finite number of distinct values. Example is the count of the number of events, such as the number of accidents per month.
binary or dichotomous variables
Can only take on two values, typically coded as 0 and 1.
Descriptive Statistics
Describe the characteristics of the distribution of values in a population or in a sample. Example is on average, AICP test takers in 2018 are 30 years old.
Inferential Statistics
Use probability theory to determine characteristics of a population based on observations made on a sample from that population. For example, we could take a sample of 25 test takers and use their average age to say something about the mean age of all the test takers.
Distribution
Overall shape of all observed data
Descriptive statistics
Procedures for depicting the main aspects of sample data, without necessarily inferring to a larger population
symmetry
It is a condition in which values are arranged identically above and below the middle of a data set or above and below the diagonal of a matrix
skewness
An asymmetric distribution, i.e., where there are either more observations below the mean or more above the mean.
kurtosis
It is a statistical description of the degree of peakedness of that distribution. For example, the ages of a sample of college freshmen would probably show kurtosis, having a high peak at age 18.
range
The difference between the largest and the smallest value.
normal (Gaussian distribution)
Bell Curve - values pile up in the center at the mean and fall off into tails at either end
Symmetric distribution
Where an equal number of observations are below and above the mean
Central tendency
The middle or center point of a set of scores. There are several ways to measure central tendency, including mean, median, and mode. The median is typically the preferred measure of central tendency.
mean
the average of a distribution. For example, the mean of [2, 3, 4, 5] is (2 + 3 + 4 + 5)/4 = 3.5. The mean is appropriate for interval and ratio scaled data
weighted mean
When there is a greater importance placed on specific entries or when representative values are used for groups of observations.
median
Middle value of a ranked distribution. The median of [2, 3, 4, 5] would be (3 + 4)/2 = 3.5. The median is the only suitable measure of central tendency for ordinal data, but it can also be applied to interval and ratio scale data after they are converted to ranked values.
mode
The most frequent number in a distribution. For example, the modes of [1, 2, 3, 3, 5, 6, 7, 7] are 3 and 7. The mode is the only measure of central tendency that can be used for nominal data, but it can also be applied to interval and ratio scale data.
variance
The variance is the average squared deviation from the mean. A larger variance means a greater spread
around the mean (flatter distribution), a smaller variance a narrower spread (a spikier distribution). Appropriate for interval and ratio scaled variables
standard deviation
Is the square root of the variance. Appropriate for interval and ratio scaled variables
degree of freedom correction
For precise coefficient estimates and powerful hypothesis tests in regression, you must have many error degrees of freedom, which equates to having many observations for each model term.
outliers
An extreme observation or measurement, that is, a score that significantly differs from all others obtained.
Coefficient of Variation
which measures the relative dispersion from the mean by taking the standard deviation and dividing by the mean. Appropriate for interval and ratio scaled variables
z-score
This is a standardization of the original variable by subtracting the mean and dividing by the standard deviation. For example, a z-score of more than 2 would mean the observation is more than two standard deviations away from the mean, or, it is an outlier in the sense just defined.
inter-quartile range (IQR)
This is the difference in value between the 75 percentile and the 25 percentile. The IQR forms the basis for an alternative concept of outliers.
Box Plot
IQR visualized. Uses two fences at the first and third quartile. Observations that are outside these fences are termed outliers
hypothesis test
A statement about a particular characteristic of a population (or several populations).
null hypothesis
The hypothesis that there is no significant difference between specified populations, any observed difference being due to sampling or experimental error.
alternative hypothesis
The research hypothesis one wants to find support for by rejecting the null hypothesis.
two-sided
An alternative hypothesis can have differences in both directions are considered
one-sided
An alternative hypothesis can have only differences in one direction are considered, i.e., only larger than or smaller than, but not both
test statistic
Provides a way to operationalize a hypothesis test.
sampling error (sampling distribution)
Error in a statistical analysis arising from the unrepresentativeness of the sample taken. The sampling error is related to the sample size, with a larger sample resulting in a smaller error
systematic error
Error in which the data values obtained from a sample deviate by a fixed amount from the true values within the population.
standard error
Pertains to the distribution of a statistic that is computed from a sample. For example, the sample average has a standard error, which is the same as the standard deviation of its sampling distribution.
statistical decision
The rejection of a null hypothesis
significance (p-value, Type I Error)
The error of rejecting the null hypothesis when it is in fact true.
confidence interval
A range of values so defined that there is a specified probability that the value of a parameter lies within it.
t-test (student’s t-test)
Typically used to compare the means of two populations based on their sample averages. A common application of the t-test is to test the significance of a regression coefficient
ANOVA (analysis of variance)
More complex form of testing the equality of means between groups. For example, we would compare the average speed of cars on a street before (control) and after a street calming infrastructure was put in place (treatment).
F-test
A slight generalization of the t-test (allowing different variances in two groups).
Chi Square test
A measure of fit. It is a test that assesses the difference between a sample distribution and a hypothesized distribution.
Chi Square distribution
A skewed distribution that is obtained by taking the square of a standard normal variable (so, it only takes positive values).
correlation coefficient
Measures the strength of a linear relationship between two variables
r-squared
The square of a correlation coefficient is often referred to as r2 (or R2)