Descriptive statistics includes statistical procedures that we use to describe the population we are studying. The data could be collected from either a sample or a population, but the results help us organize and describe data. Descriptive statistics can only be used to describe the group that is being studying. That is, the results cannot be generalized to any larger group. Inferential statistics is concerned with making predictions or inferences about a population from observations and analyses of a sample. That is, we can take the results of an analysis using a sample and can generalize it to the larger population that the sample represents. In order to do this, however, it is imperative that the sample is representative of the group to which it is being generalized. Starting point of analysis is determining the level of measurement of unit of analysis.

Measures of central tendency
Aim: to (univariately) describe the distribution of variables on different levels of measurement MEAN
Mean: a first a first measure of central tendency
for the sample: for the population:

Characteristics of the mean:
* Changing a score will change mean
* Adding or removing a score will change mean (unless the score is equal to mean) * Adding, subtracting, multiplying, dividing each score by a constant value causes mean to change accordingly * Sum of differences from the mean is zero:

* Sum of squared differences from the mean is minimal or Sum of Squares (SS) a larger SS means that scores deviate more from the mean
Why minimal?
‘Minimal’ because if we had used any other value than the mean (5) to subtract, SS would have been larger than 42

MEDIAN
A second measure of central tendency: the median (ordinal)
to find the median:
1) sort all cases based on their value on x
2) the value of the „middle case“ equals the median (equal amount of cases below and above)

Note that the median is not responsive to outliers like...

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D. The river/lake where a fish was captured
4. Managers study the number of days per month over the last year that employees in the payroll department called in sick to determine the averages they can expect next year. Collecting the data and determining the averages last year is an example of what type of statistics? Determining the averages they can expect next year is an example of what type of statistics?
A. They are both examples of inferential statistics because averages are inferred in both instances.
B. Inferential statistics; descriptive statistics.
C. They are both examples of descriptive statistics because they deal with analyzing data.
D. Descriptive statistics; inferential statistics.
5. The grades that a random sampling of students in the psychology degree program received over the last decade of "Abnormal Psychology" classes are an example of what statistical concept?
A. The grades are an example of a parameter.
B. The grades are an example of a sample.
C. The grades are an example of a population.
D. The grades are an example of a statistic.
6. What method is used to sample a population so that it is representative of the population?
A. All but the samples that appear to have the lowest and highest values are selected.
B. Samples are chosen at random from the...

...What are the characteristics of a population for which a mean/median/mode would be appropriate? Inappropriate?
The analysis of data begins with descriptive statistics such as the mean, median, mode, range, standard deviation, variance, standard error of the mean, and confidence intervals. These statistics are used to summarize data and provide information about the sample from which the data were drawn and the accuracy with which the sample represents the population of interest. The mean, median, and mode are measurements of the “central tendency” of the data. The range, standard deviation, variance, standard error of the mean, and confidence intervals provide information about the “dispersion” or variability of the data about the measurements of central tendency.
MEASUREMENTS OF CENTRAL TENDENCY The appropriateness of using the mean, median, or mode in data analysis is dependent upon the nature of the data set and its distribution (normal vs non-normal). The mean (denoted by x) is calculated by dividing the sum of the individual data points (where Σ equals “sum of”) by the number of observations (denoted by n). It is the arithmetic average of the observations and is used to describe the center of a data set.
mean=x= One of the most basic purposes of statistics is simply to enable us to make sense of large numbers. For example, if you want to know how the students in your school are doing in the statewide achievement...

...Descriptive Statistics Paper
By
September 27, 2010
In this paper Team B will examine the data that we have collected and we will draw a conclusion based on your findings, to get to the conclusion we will analyze the data using descriptive statistics, we will calculate the measures of central tendency, and dispersion, we will also show all the information with graphics and tables for a better understanding of the date, after all these steps are executed we will draw our conclusion.
Data Analysis Using Descriptive Statistics
Through this paper, Team B will use the philosophy of descriptive statistics to describe the main feature of the collection of data quantitatively (Main PS 1995). Descriptive statistics will provide simple summaries about the samples and the measures. In essence, we will show a summary of the data that the team has collected. Some of the ways that we will show the data collected will be in the form of first central tendency which is the distribution locates the center of a distribution of values. The three types of the central tendency are the mean, the median and the mode. Secondly, we will look at the dispersion which is the spread of values around the central tendency (Dodge 2003). The standard deviation is a more accurate way of measuring the dispersion. Thirdly, the use of graphics and tables to illustrate the data collected in a visual background. Fourthly there...

...Descriptive Statistics: Real Estate
University of Phoenix
RES/341 Research and Evaluation I
Descriptive Statistics: Real Estate
Does having a pool increase the price of houses that have the same number of bedroom? In order to answer that question, we divided our data set into two groups; houses with 1 to 3 bedrooms and houses with 4 and more bedrooms. We then compared the prices of houses with a pool to houses without a pool in each group. Different calculations were used to determine the central tendency, dispersion, and the skew of our data. The central tendency helps to simplify data and also to predict future results. We can use diverse calculations to measure it such as the mean, mode, and median. According to our sample of houses with 1 to 3 bedrooms, the mean price was higher of $4,060 for houses without a pool than with a pool. The same rule applies to houses with more than 4 bedrooms, but with a larger difference of $51,170. Another way we used to calculate the central tendency is by finding the median. The medians are also higher in each group for houses without a pool than those with a pool.
To better answer the above question, we also analyzed the skewness of our data in the two groups. . If we look at the two groups, houses with 1 to 3 bedrooms and houses with 4 or more bedrooms, the data seems to be skewed to the right because the mean is larger than the median. However, due to the small difference between the...

...Air Force Assignment
1. Use appropriate descriptive statistics to summarize the training time data for each method. What similarities or differences do you observe from the sample data?
Descriptive analysis in excel has been used to come up with relevant figures of the given data samples which is tabulated below:
Descriptive Statistics | Current | Proposed |
Mean | 75.06557 | 75.42623 |
Standard Error | 0.505094 | 0.32091 |
Median | 76 | 76 |
Mode | 76 | 76 |
Standard Deviation | 3.944907 | 2.506385 |
Sample Variance | 15.5623 | 6.281967 |
Kurtosis | -0.06933 | 0.58694 |
Skewness | -0.22053 | -0.28749 |
Range | 19 | 13 |
Minimum | 65 | 69 |
Maximum | 84 | 82 |
Sum | 4579 | 4601 |
Count | 61 | 61 |
Analysis of descriptive statistics shows that both the current and the proposed plan have almost similar mean completion hours which stand at 75.06 and 75.42 for the current and proposed respectively. Both the plans have exact same median and mode. However, the standard deviation in the current plan (3.94) is higher than that in the proposed plan (2.56), which is ultimately leading to the higher variance in the current plan. This suggests that the completion hours are more dispersed the mean value in the current plan, hence the mean does not give the true picture of data distribution whereas in the proposed plan, data for completion hours is comparatively more congregated.
2. Use the methods of...

...Descriptive Statistics paper
RES/341
July 24, 2011
Descriptive Statistics paper
The information below is a continuance of week two, week three, and on week four. The previous assessment in week two on “real estate research” for thinking of hypothesis on home values in Alvarado, Texas. The evaluating on real estate prices reveals a purpose of this research paper and its importance findings. The discoveries include problem definition, and on variables.
The next assessment was on week three on “data collection” on reviewing literatures, sampling design, and on any ethical concerns with collection data on the same topic. A summary was assembled in week three on terms of population, sampling size, and factors on real estate. This research found house prices to change in each different region.
This is week four paper on “descriptive statistics” on real estate in Alvarado, Texas. The information below will consist of; data analysis, data using graphic and tabular techniques, and on skew values, histogram measures, and on central tendency.
The Central tendency is the measures of numerical summaries used to summarize data with a one number. The most common used are mode, mean, and median. The Hypothesis is "homes more or less expensive fifteen miles away from the center of the city"? The comparison will come from the City of Arlington, Texas, and Cedar Hill. The mode is the data that happens most frequently in the data...

...Descriptive and Inferential Statistics
Greg Hagen, Jean Parker, Jade Riley, Nanika Woods, Myron Hamilton, Tajah Gutierrez, Treva Eley
PSY/315
June 9, 2012
Nancy A. Walker
Descriptive and Inferential StatisticsStatistics is a vital part of the psychological field as the analysis of statistics provides researchers with a means of both describing the results of research and surmising from those results, as well as drawing conclusions related to a hypothesis. Statistics gives a better understanding and exact description of a phenomenon of nature when in the field of study and includes data collection, data analysis, interpretation of, and making inferences from the data.This analysis is usually done on information that has been assembled in the form of graphs and charts of various types. Essentially, there are two branches of methodology involving statistics, descriptive statistics and inferential statistics, with descriptive statistics describing the research, and inferential statistics making inferences from it. Without statistics, researchers would have little foundation for the validation of their theories.
“Statistics is a form of math and this math is used when concerning analyzing, organizing as well as interpreting groups of numbers” (Aron, A., Aron E. N., & Coups, E. J., 2009)....

...Stem-and-leaf displays and dot plots are useful for detecting
Student Answer:
Outliers
Skewness
Midpoint of data
All of the above
Points Received: 1 of 1
Comments:
4. Question : When a population is skewed to the left or right with a very long tail, what is the best measure to use for central tendency.
Student Answer: Population mean
Population mode
Population median
Population standard deviation
Points Received: 1 of 1
Comments:
5. Question : The science of using a sample to make generalizations about the important aspects of a population is known as
Student Answer: Statistical Process Control.
Descriptive Statistics.
A random sample.
Statistical Inference.
Points Received: 1 of 1
Comments:
6. Question : The standardized value of any value in a population or sample is called
Student Answer: percentile
coefficient of variation
quartile
Z-score
Points Received: 1 of 1
Comments:
7. Question : It is appropriate to use the Empirical Rule to describe a population that is extremely skewed.
Student Answer: True
False
Points Received: 1 of 1
Comments:
8. Question : The population mean is the average of the population measurements.
Student Answer:
True
False...