Competency 2.2 Flashcards
What is a Histogram?
it is a bar graph in which the frequencies are represented by the lengths of the bars
What is a Frequency Polygon?
is a line graph formed by connecting the frequencies of the values
Skewed distributions
occasionally data may be grouped into a distribution that has multiple data points on one or the end of spectrum.
What are Inferential statistics?
They include methods used to examine a sample of a population and make inferences about and entire population based on analysis of the sample data.
What is Proportion?
It is a statement of equity between two categories. For example object class 12 has an historic relationship with object class 11 of 25%.
What is percentage changes?
It is from the starting to the ending value and expressed as positive changes for increases and negative changes for decreases.
What is a Correlation Coefficient?
It is a number between -1 and 1 that measures the degree to which two variables are linearly related. If there is a perfect linear relationship, all data points on a straight line, we have a correlation coefficient of 1 for a positive correlation and -1 for a negative correlation and we have strong predictability.
Value greater than .8 or -.8 is considered strong and anything less than .5 or -.5 is considered weak.
What is Linear Regression?
If we think that linear relationship may exist between the variables, we can plot the data and determine a “best fit” straight line through the data.
What is Coefficient of Determination?
It is simply the square of r. By squaring, this provides a positive number between 0 and +1. The larger the number the stronger the relationship.
What is Coefficient of Variation?
It measures the amount of dispersion expressed as a decimal or a percentage. The smaller the value, the better the predictability.
What are constant dollars?
They are the result of having the effects of inflation removed. They are always associated with “base year”. To be in constant dollars, the analyst must adjust the costs so they reflect base-year prices for all time periods. They help determine the true cost changes of a system, activity or item. Only need to be adjusted after the calendar year in which the estimate has been prepared.
What are Current Dollars?
They are expressed in the value of the year in which a cost is expected to occur and therefore reflect the effect of inflation. Prior year cost are stated as the actual dollars spent. When future-year dollars are stated in current year dollars, the figures given are the amounts that should be programmed under the full-funding concept.
What are sunk cost?
They are past expenditures from prior fiscal years. They are excluded from economic analysis computations.
Present Value Factor is
PFV=1/(1+d)t
PVF1 = 1/(1+.045)^1 =.9569 PVF2 = 1/(1+.045)^2 =.9157 PVF3 = 1/(1+.045)^3 =.8763
Calculate Discount Rate
# Cost Benefit disc 4.5% 2X4 3X4 1 $10.00 $0.00 0.9782 $9.78 $0.00 2 $20.00 $0.00 0.9361 $18.72 $0.00 3 $30.00 $35.00 0.8958 $26.87 $31.35 4 $30.00 $50.00 0.8572 $25.72 $42.86 5 $10.00 $75.00 0.8203 $8.20 $61.52 Total $89.30 $135.74
NPV = Benefits - costs $46.44
