CHE 105 Q1

____ is defined by error

accuracy using absolute and relative error computation

What are the two types of errors?

random and systematic

__ are indeterminate and reflect in the scatter of the data

random errors

What type of distribution do random errors follow?

gaussian distribution

the relationship between error and number of measurements (N)

as N increases, error decreases and results approaches the true value

__ is determinant, with assignable sign and magnitude that will be the same across all measurements

systematic error

What are the three types of systematic error?

instrumental, method, and personal

How might you address instrumental errors?

frequent calibration of the instrument using reference standards

How might you address method errors?

validate the method by using reference standards

How might you address personal errors?

by having care and self discipline as to not be prejudice and cause bias

__ is measured by the statistical application of the gaussian distribution (mean, std dev, variance)

precision

Absolute deviation

z = (x - µ) / σ

Gaussian properties

1. the mean is the most frequently observe value in the data set

2. the distribution is symmetrical around the mean

3. small divergences are more frequently observed than large ones

4. with the lack of systematic error, the mean of a large set of data approached the true value

What is the percent that a single measurement can be found within σ of the mean

68%

What is the percent that a single measurement can be found within 2σ of the mean

95%

What is the percent that a single measurement can be found within 3σ of the mean

99.7%

The σ of the mean is referenced as __ which decreases by 2 for every 4 measurements

standard error of the mean

What methods are used to estimate σ from a sample std. dev?

1. increase the number of measurements

2. use a pooled average

3. use a confidence interval

__ is an interval that we can expect the true mean to lie with a degree of probability

confidence interval

What method is used when the std dev of a sample is unknown?

use the t-statistic to substitute σ

__ computes the significance in the difference between the true value and known value

hypothesis testing

What does rejecting the H(0) indicate?

rejecting the null indicates systematic bias

__ is the probability that the true value is outside of the confidence interval

α (alpha)

What is the method of least squares provide us?

provides us with a linear relationship that best fits the data and minimizes the residual between the line and the data point

__ electronics have a continuous signal, measure bulk measurements such as volume and weight, and have AC and DC

analog

__electronics have discrete signal (1 and 0), are used for computers and microprocessors, and use a ADC to convert analog to digital by making the signal discrete.

digital

Why electronics are important to study

1. The transduction process occurs to convert the chemical/physical response to an electrical signal. this signal must be accurate to the respose

2. computer interfaces need effective communication between analog and digital to display data

At t=0, what happens to the capacitor of a circuit?

you have a short circuit and the capacitor acts as a wire in that instant

At t=∞, what happens to the capacitor?

the capacitor becomes charged (became the battery) or discharged and the current stop flowing

__ are exponentially time dependent and depend on the changes in current and voltage

capacitors

What is Tau (τ)?

it is the time constant that measures the time it takes for a capacitor to charge or discharge

Why do actual circuit signals not behave ideally? e.i it is a curve instead of a discrete uniform signal

the charging capacitance limits the circuit speed and real circuit wires have resistance