Descriptive Statistics Flashcards
is one of the ways to numerically describe gathered information. Perhaps we can consider part of the articles below for us to learn more about some of the many uses of MCT. The given examples illustrate how can we apply concepts of measure of central tendency specifically the mean and the mode.
measure of central tendency
The most common average
arithmetic mean
The sum of all the values of the observations divided by the number of observations
arithmetic mean
arithmetic mean is denoted by what greek letter for population
mu (ΞΌ)
the sample mean, used to estimate the population mean ΞΌ, is computed as:
π₯Μ =(β1(π=1)^π π₯π )/π
The positional middle of an array
median
In an array, one-half of the values precede the median and one-half follow it
medianmed
median formula if odd
ππ=π(((π+1))/2
median formula if even
ππ=(ππ/2)+π(π/2+1))/2
It is the observed value that occurs most frequently.
mode
It locates the point where the observation values occur with the greatest density.
mode
It does not always exist, and if it does, it may not be unique
mode
if there is only one mode
unimodal
if there are two modes
bimodal
if there are three mode
trimodal
It is not affected by extreme values.
mode
It can be used for qualitative as well as quantitative data.
mode
are values below which a specified fraction or percentage of the observations in a given set must fall. Some board exam results are based on this, specifically percentile. Letβs say a board passer has a percentile rating of 93%, it doesnβt mean that he was able to get 93% of the correct answer. This just indicate that his score in the board exam is above the score of 93% of all board examinees.
measures of location or fractiles
are values that divide a set of observations in an array into 100 equal parts.
percentiles
percentile formula
ππ=π‘βπ π£πππ’π ππ π‘βπ ((π(π+1))/100)^π‘β πππ πππ£ππ‘πππ ππ π‘βπ πππππ¦
are values that divide the array into 10 equal parts
deciles
are values that divide the array into 4 equal parts.
quartiles
decile formula
(π(π+1)/10)^π‘β
quartile formula
(π(π+1)/4)^π‘β
practice finding the percentile, quartile, decile
+1
identify the level of measurement given: Color of M&Ms preferred by children 5-8 years old
nominal
the level of measurement which measures only identity and magnitude is called nominal
t/f
false
a study found that eating garlic has a 15% chance of lowering blood pressure
descriptive or inferential?
inferential
in the interval level of measurement, a true absolute zero exists
t/f
false
A quality inspector took a sample of 40 bolts from a large shipment and measures the length of each. He finds that 34 of them, or 85%, meet the length specification. What does it mean?
Proportion of the good bolts in the shipment is likely to be close to 85%.
Find the value of x that will make the mean equal to 12: 12, 7, 18, 15, 11,9, x.
12
Sixty-two of last yearβs high school graduates in public and private schools are now enrolled in college or university.
inferential or descriptives?
descriptives
Identify the type of variable given: Type of vehicle owned
qualitative
Identify the level of measurement given: Price of gasoline within Cavite
ratio
Identify the type of variable given: Quantity of electronic equipment bought
quantitative discrete
Identify the type of variable given: Electricity consumption in watts
quantitative continuous
Identify the type of variable given: Weight of paper usage
quantitative continuous
25, 30, 18, 18, 27, 15, 15, 30?
how many modes
trimodal
Which of the following is true for the mean of a data set?
It is a positional value in an arranged data set
Data set may have more than one mean
The mean can be used for both qualitative and quantitative data sets
Extreme values in the data set tend to affect the mean
Extreme values in the data set tend to affect the mean
Identify the level of measurement given: number of household members of residents in Dasmarinas
ratio
Data taken by a researcher from news articles is primary
t/f
false
Which of the following statement would best describe the study βA survey of 1,000 people reveals that they belink their eyes 12 times per minute on averageβ
This is an example of descriptive statistics, since β12 times per minuteβ is a result of collected survey data
According to the Philippine Statistics Authority, the growing number of Cavite inhabitants may be attributed to rapid birth rate and migration spillover from Metro Manila Residents. Given the annual population growth, the figure could reach 4,822,580 in 2020
This is an example of inferential statistics, since 4,822,580 is a prediction
Identify the level of measurement given: television show ratings in the Philippines (General Patronage βGβ, Parental Guidance βPGβ and Strong Parental Guidance βSPGβ)
Ordinal
An applied mathematics student wanted to create a linear programming model to minimize the carbon footprint left in the atmosphere by the college students and faculty in DLSU-D. To do this, the student had to gather information on electricity consumption in watts, transportation costs, weight of paper usage, type of vehicle owned and quantity of electronic equipment bought. What is the population of the study?
The set of all college students and faculty in DLSU-D
Identify the type of variable given: transportation costs
Quantitative Continuous/Descriptive
Due to impeding excise tax imposition, it is predicted that there will be decrease of automobiles next year
I/D?
inferential statistics
A numerical value used as a summary measure for a sample, such as sample mean, is known as what?
sample statistic
Inferential statistics deals with making generalizations about a body of data where only a part of it is examined
T/F
true
Identify the level of measurement given: Exact time of arrival of domestic flights at NAIA terminal 3 (as reflected on clock)
Interval
Time to finish this long quiz is an example of discrete variable.
T/F
False
As of the 2015 census, Cavite was found the most populous with 3.68 million people, followed by Bulacan at 3.29 million, Laguna with 3.04 million and there were 24 other provinces that surpassed the one million population mark.
D/I?
descriptive statistics
what graph is used for interval and frequency (2)
bar
pie
what graph is used to compare TCB and frequency
Histogram
what graph is used to compare class mark and %
frequency polygon
what graph is used to compare <CF>CF vs LTCB</CF>
ogives
