Ch 2 Measures of Central Tendency Flashcards
The prime measure of central tendency is the
mean
Here is a table showing 18 rents. Monthly rents $975 $850 $1025 1100 1000 950 1000 925 1050 850 925 950 975 1000 1000 1025 1050 1100 What is the modal rent?
The Modal is $1,000
The symbol ______ stands for “the sum of.”
Sigma
Here is a table showing 10 GRMs. GRMs 98.5 93.6 112.8 122.0 104.2 91.7 98.8 114.2 117.9 123.5 What is the median GRM?
108.5. First you must array them in order: 91.7, 93.6, 98.5, 98.8, 104.2, 112.8, 114.2, 117.9, 122, 123.5. There are 10 numbers in the array. The formula to find the median is n + 1 ÷ 2. 10 + 1 ÷ 2 = 5.5. The median is the number that is halfway between the 5th and 6th from either end. Count in from either end and the 5th and 6th numbers are 104.2 and 112.8. The number that lies halfway between 104.2 and 112.8 is 108.5. That’s the median.
“The listing of a set of observations, such as sales ratios, in a specific order, e.g., alphabetical, alpha-numeric, chronological, order of magnitude” is the definition of
array. An array is list of numbers in order (from low to high or high to low).
A decile divides the data into ___ equal parts.
10
The symbol for a variant is
X
“In statistics, a subset of a population selected for analysis” is the definition of
sample
Every distribution of numbers has a(n) ____________ but there may not be a _____________.
mean and median, mode
Here is a table showing 10 GRMs. GRMs 98.5 93.6 112.8 122.0 104.2 91.7 98.8 114.2 117.9 123.5 What is the mean GRM?
107.7. f CLEAR S 98.5 S+ 93.6 S+ 112.8 S+ 122 S+ 104.2 S+ 91.7 + 98.8 S+ 114.2 S+ 117.9 S+ 123.5 S+ g
The most frequently occurring value in an array of numbers is the
mode
True or False: Fractiles are intervals that total 100% of the distribution.
TRUE
“A number that describes a characteristic of a population” is the definition of
parameter. A parameter is the term we use to define a characteristic of a population. A parameter could be number of square feet.
“The central point, or representative value, around which items cluster in a frequency distribution” is the definition of
central tendency
Here is a table showing 18 rents. Monthly rents $975 $850 $1025 1100 1000 950 1000 925 1050 850 925 950 975 1000 1000 1025 1050 1100 What is the median rent?
- First you must array them in order: 850, 850, 925, 925, 950, 950, 975, 975, 1000, 1000, 1000, 1000, 1025, 1025, 1050, 1050, 1100, 1100. There are 18 numbers in the array. The formula to find the median is n + 1 ÷ 2. 18 + 1 ÷ 2 = 9.5. The median is the number that is halfway between the 9th and 10th from either end. Count in from either end and the 9th and 10th numbers are 1000 and 1000. The number that lies halfway between 1000 and 1000 is 1000. That’s the median.
The _______ describes the central position in an array.
median
Here is a table showing 10 GRMs. GRMs 98.5 93.6 112.8 122.0 104.2 91.7 98.8 114.2 117.9 123.5 What is the mean GRM?
107.7. f CLEAR S 98.5 S+ 93.6 S+ 112.8 S+ 122 S+ 104.2 S+ 91.7 + 98.8 S+ 114.2 S+ 117.9 S+ 123.5 S+ g
Parameters are used to characterize a __________; statistics are used to measure a ___________.
population, sample
What is the mode in the following list of rental amounts for two-bedroom apartments? $850, $885, $910, $825, $800, $900, $925
there is no mode
“In statistics, a population or entire body of data” is the definition of
universe
Here is a table showing 18 rents. Monthly rents $975 $850 $1025 1100 1000 950 1000 925 1050 850 925 950 975 1000 1000 1025 1050 1100. What is the mean rent?
986.11. f CLEAR S 975 S+ 850 S+ 1025 + 1100 S+ 1000 S+ 950 S+ 1000 S+ 925 S+ 1050 S+ 850 S+ 925 S+ 950 S+ 975 S+ 1000 S+ 1000 S+ 1025 S+ 1050 S+ 1100 S+ g Answer is $986.11
Looking for a central tendency is part of xx
descriptive statistics.
In statistics, a population or entire body of data; used to distinguish between a population and a sample obtained from the population. Population is a more generally used term.
Universe
Universe is also commonly called population.
In statistics, a subset of a population selected for analysis. defines
Sample
- A constant or value used to index a function, such as use of degrees of freedom to derive an appropriate t-statistic or F-statistic function.
- A number that describes a characteristic of a population. defines
parameter
The sum of all the observations within a population; e.g., the aggregate sale price of all the houses sold in a given community. defines
Aggregate
xx intervals that total 100% of the distribution.
Fractiles are
A quartile is equal to
one-fourth of the data set
A x divides the data set into 10 equal parts. That becomes useful if you have a x data set.
decile
large
