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How do you work out concentrations of an unknown sample on excel when the lowest standard is too low to be read the unknown falls below the range of the second lowest standard?
Wiki User
∙ 10y ago
add 100, or 1000 to every number in the series so they all fall above the lower limits, then just subtract that number when you publish your results.
Wiki User
∙ 10y ago
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What condition should use the standard addition method?
The standard addition would be used when determining the concentration of a sample because of matrix effect problems (matrix effect occurs when unknown sample contains many impurities).
Which sample had the lowest final temperature?
white
What is the components of unknown polysaccharide sample?
peptidoglycon chain
What sample most likely has the lowest density?
Liquid mercury
when is flame test used?
to identify an unknown sample by its emission spectrum
When the population standard deviation is not known the sampling distribution is a?
If the samples are drawn frm a normal population, when the population standard deviation is unknown and estimated by the sample standard deviation, the sampling distribution of the sample means follow a t-distribution.
What is the difference between t-distribution and standard normal distribution?
the t distributions take into account the variability of the sample standard deviations. I think that it is now common to use the t distribution when the population standard deviation is unknown, regardless of the sample size.
When to use z or t-distribution?
If the sample size is large (>30) or the population standard deviation is known, we use the z-distribution.If the sample sie is small and the population standard deviation is unknown, we use the t-distribution
What condition should use the standard addition method?
The standard addition would be used when determining the concentration of a sample because of matrix effect problems (matrix effect occurs when unknown sample contains many impurities).
How do you make a standard curve graph?
Standard curves are used to determine the concentration of substances. First you perform an assay with various known concentrations of a substance you are trying to measure. The response might be optical density, luminescence, fluorescence, radioactivity or something else. Graph these data to make a standard curve - concentration on the X axis, and assay measurement on the Y axis. Also perform the same assay with your unknown samples. You want to know the concentration of the substance in each of these unknown samples. To analyze the data, fit a line or curve through the standards. For each unknown, read across the graph from the spot on the Y-axis that corresponds to the assay measurement of the unknown until you intersect the standard curve. Read down the graph until you intersect the X-axis. The concentration of substance in the unknown sample is the value on the X-axis. In the example below, the unknown sample had 1208 counts per minute, so the concentration of the hormone is 0.236 micromolar. Prism makes it very easy to fit your standard curve, and to read (interpolate) the concentration of unknown samples.
How does one calculate the standard error of the sample mean?
Standard error of the sample mean is calculated dividing the the sample estimate of population standard deviation ("sample standard deviation") by the square root of sample size.
What is a flame tested used for?
To identify an unknown sample by its emission spectrum
Can the five-number summary be used to calculate the standard deviation?
No. To calculate a sample standard deviation one requires the sample values. The five-number summary provides only the lowest value, the highest, the median, and the upper and lower quartiles. In any sample of size greater than five some values will be missing from the summary.
When to you use a z-scores or t-scores?
T score is usually used when the sample size is below 30 and/or when the population standard deviation is unknown.
What branch of chemistry carries out tests to identify an unknown substance?
Analytical chemistry is concerned with investigation of the quantitative and/or qualitative characteristics of a given sample. For instance, an analytical chemist may qualitatively determine what the various polycyclic aromatic hydrocarbons in a tar sample are, and may also quantitatively analyze the concentrations of each species in the sample.
What is the sample standard deviation of 27.5?
A single observation cannot have a sample standard deviation.
How does sample size affect the size of your standard error?
The standard error should decrease as the sample size increases. For larger samples, the standard error is inversely proportional to the square root of the sample size.The standard error should decrease as the sample size increases. For larger samples, the standard error is inversely proportional to the square root of the sample size.The standard error should decrease as the sample size increases. For larger samples, the standard error is inversely proportional to the square root of the sample size.The standard error should decrease as the sample size increases. For larger samples, the standard error is inversely proportional to the square root of the sample size.
