Collecting and Processing Information
In this note, you will find information explaining why we need data, but also how to collect and process it.
Why do we need data?
Data is used throughout the Engineering Design Process to optimize designs and improve efficiency during production
Statistics refer to the collection and organization of data(science) as well as the analysis and presentation of those data(mathematics)
Statistics are often evaluated using the assistance of computers and software such as Microsoft Excel
Such tools allow user to easily access, collect, organize, maintain, manipulate, and interpret data – which helps to improve efficiency
Basic Statistics Vocabulary:
Mean - the average of a given data set
Median - the middle number in a given ordered set
Mode - the most frequently occurring number in a given data set
Standard Deviation - how much variation exists from the average(mean) in a given data set
Range - the distribution of the data set or the difference between the largest and smallest values
Tolerance - the amount of characteristic(product/part/dimension/etc) can vary without compromising(affecting) the overall function or design of the product
Normal size - the size used in the general description of a part/product
Basic size - the converted normal size(fraction to decimal) that can produce some deviation
Upper Specification Limit - the highest acceptable deviation or value for a characteristic
Lower Specification Limit - the lowest acceptable deviation or value for a characteristic
Mean - the average of a given data set:
x = represents the data set
∑ = the sum of a mathematical operation
n = the total number of variables in the data set
Equation for mean = ∑x/n
Add the numbers in the data set first, then divide the product by the number of variables
Median - the middle number in a given ordered data set
If the given data set has an even number of data, the median is the average of the two center data
Add the two numbers together then divide the product by 2
Mode - the most frequently occurring number in a given data set
Standard Deviation - Standard Deviation (SD) is a UNIT. It is used to measure the variability of individual data to the mean.
The smallest value that the standard deviation can be is 0. Standard deviation can not be negative.
Standard Deviation Steps Explained:
The mean must first be found through adding all numbers in a data set, and dividing by the pieces of data within the data set.
Subtract the mean from each value
Square the differences
Find the average of the squared numbers to find the variance
Square the variance to find the standard deviation
Calculating Standard Deviation
Equation for Standard Deviation = ∑(xi – μ)²
√ n - 1
xi = represents the individual data
μ = represents the mean of the data set
∑ = the sum of a mathematical operation
n = the total number of variables in the data set
The range is the distribution of the data set or the difference between the largest and smallest values in a data set
Engineering tolerance is the amount a characteristic can vary without compromising the overall function or design of the product.
Tolerances generally apply to the following:
Physical dimensions (part and/or fastener)
Physical properties (materials, services, systems)
Calculated values (temperature, packaging)
American National Standards Institute (ANSI) standards.
Examples:
Bilateral Tolerance (1.125 0.025)
Unilateral Tolerance (2.575)
In this note, you will find information explaining why we need data, but also how to collect and process it.
Why do we need data?
Data is used throughout the Engineering Design Process to optimize designs and improve efficiency during production
Statistics refer to the collection and organization of data(science) as well as the analysis and presentation of those data(mathematics)
Statistics are often evaluated using the assistance of computers and software such as Microsoft Excel
Such tools allow user to easily access, collect, organize, maintain, manipulate, and interpret data – which helps to improve efficiency
Basic Statistics Vocabulary:
Mean - the average of a given data set
Median - the middle number in a given ordered set
Mode - the most frequently occurring number in a given data set
Standard Deviation - how much variation exists from the average(mean) in a given data set
Range - the distribution of the data set or the difference between the largest and smallest values
Tolerance - the amount of characteristic(product/part/dimension/etc) can vary without compromising(affecting) the overall function or design of the product
Normal size - the size used in the general description of a part/product
Basic size - the converted normal size(fraction to decimal) that can produce some deviation
Upper Specification Limit - the highest acceptable deviation or value for a characteristic
Lower Specification Limit - the lowest acceptable deviation or value for a characteristic
Mean - the average of a given data set:
x = represents the data set
∑ = the sum of a mathematical operation
n = the total number of variables in the data set
Equation for mean = ∑x/n
Add the numbers in the data set first, then divide the product by the number of variables
Median - the middle number in a given ordered data set
If the given data set has an even number of data, the median is the average of the two center data
Add the two numbers together then divide the product by 2
Mode - the most frequently occurring number in a given data set
Standard Deviation - Standard Deviation (SD) is a UNIT. It is used to measure the variability of individual data to the mean.
The smallest value that the standard deviation can be is 0. Standard deviation can not be negative.
Standard Deviation Steps Explained:
The mean must first be found through adding all numbers in a data set, and dividing by the pieces of data within the data set.
Subtract the mean from each value
Square the differences
Find the average of the squared numbers to find the variance
Square the variance to find the standard deviation
Calculating Standard Deviation
Equation for Standard Deviation = ∑(xi – μ)²
√ n - 1
xi = represents the individual data
μ = represents the mean of the data set
∑ = the sum of a mathematical operation
n = the total number of variables in the data set
The range is the distribution of the data set or the difference between the largest and smallest values in a data set
Engineering tolerance is the amount a characteristic can vary without compromising the overall function or design of the product.
Tolerances generally apply to the following:
Physical dimensions (part and/or fastener)
Physical properties (materials, services, systems)
Calculated values (temperature, packaging)
American National Standards Institute (ANSI) standards.
Examples:
Bilateral Tolerance (1.125 0.025)
Unilateral Tolerance (2.575)