What are the three types of nuclear change?
Nuclear Reactions
- Fission.
- Fusion.
- Nuclear Decay.
- Transmutation.
What is a nuclear reaction example?
An important example of nuclear fission is the splitting of the uranium-235 nucleus when it is bombarded with neutrons. Various products can be formed from this nuclear reaction, as described in the equations below. Another important example of nuclear fission is the splitting of the plutonium-239 nucleus.
How does a nuclear reaction start?
A neutron collides with a Uranium-235 atom. This extra neutron creates unstable Uranium-236 isotopes, which split almost instantly. This splitting produces heat, which is converted into energy for power, and it produces two neutrons which continue the process, called a chain reaction.
What is Q value in nuclear physics?
In nuclear physics and chemistry, the Q value for a reaction is the amount of energy absorbed or released during the nuclear reaction. The value relates to the enthalpy of a chemical reaction or the energy of radioactive decay products. It can be determined from the masses of reactants and products.
What is Q-value formula?
The “Q-value” of the decay, Qα is the difference of the mass of the parent and the combined mass of the daughter and the α-particle, multiplied by c2. Qα = (mP − mD − mα)c2. The mass difference between the parent and daughter nucleus can usually be estimated quite well from the Liquid Drop Model.
How is Q-value calculated?
Here’s how to calculate a Q-value:
- Rank order the P-values from all of your multiple hypotheses tests in an experiment.
- Calculate qi = pi N / i.
- Replace qi with the lowest value among all lower-rank Q-values that you calculated.
How do you interpret Q-value?
This is the “q-value.” A p-value of 5% means that 5% of all tests will result in false positives. A q-value of 5% means that 5% of significant results will result in false positives. Q-values usually result in much smaller numbers of false positives, although this isn’t always the case..
What does P and Q stand for in statistics?
p refers to the proportion of sample elements that have a particular attribute. q refers to the proportion of sample elements that do not have a particular attribute, so q = 1 – p.
What Q-value is significant?
A FDR of 5% means that among all features called significant, 5% of these are truly null on average. The q-values can be used to filter your data according to the error rate among your accepted entries. So if you set a threshold of q-value ≤ 0.01, you are applying an FDR threshold of 1%.
What is the difference between the Q-value and Bonferroni corrected P value?
Because of this, it is less conservative that the Bonferroni approach and has greater ability (i.e. power) to find truly significant results. An FDR adjusted p-value (or q-value) of 0.05 implies that 5% of significant tests will result in false positives. The latter will result in fewer false positives.
Is P value false positive rate?
The False Positive Problem When a statistical hypothesis test produces significant results, there is always that chance that it is a false positive. For example, a P value near 0.05 often has a false positive error rate of between 23-50%.
What is p value in gene expression?
The P-value is the probability for the experimental outcome as observed or more extreme, if there is no difference in expression between the experimental conditions. The P-value can serve as a probability measure to select differentially expressed genes from a pre-specified significance level (cutoff threshold).
What is corrected P value?
The adjusted P value is the smallest familywise significance level at which a particular comparison will be declared statistically significant as part of the multiple comparison testing.
How is Bonferroni corrected P value?
To get the Bonferroni corrected/adjusted p value, divide the original α-value by the number of analyses on the dependent variable.
Can adjusted p value be greater than 1?
As such, any corrected p-value <= 0.05 should be considered significant and p-values can be > 1.
Why do you adjust p values?
A p-value adjustment is necessary when one performs multiple comparisons or multiple testing in a more general sense: performing multiple tests of significance where only one significant result will lead to the rejection of an overall hypothesis.
What does an adjusted p-value of 1 mean?
no evidence at all
Why do you need a different p-value if you do multiple independent tests?
The rationalists have the following objections to that theory: 1) P-value adjustments are calculated based on how many tests are to be considered, and that number has been defined arbitrarily and variably; 2) P-value adjustments reduce the chance of making type I errors, but they increase the chance of making type II …
How do you find the adjusted p-value?
<p(m) are the ordered unadjusted p-values. Following the Vladimir Cermak suggestion, manually perform the calculation using, adjusted p-value = p-value*(total number of hypotheses tested)/(rank of the p-value), or use R as suggested by Oliver Gutjahr p.
What is the Bonferroni test used for?
The Bonferroni test is a statistical test used to reduce the instance of a false positive. In particular, Bonferroni designed an adjustment to prevent data from incorrectly appearing to be statistically significant.
How is FDR P-value calculated?
FDR = E(V/R | R > 0) P(R > 0)
- You have at least one rejected hypothesis,
- The probability of getting at least one rejected hypothesis is greater than zero.
Why do we need Bonferroni correction?
Purpose: The Bonferroni correction adjusts probability (p) values because of the increased risk of a type I error when making multiple statistical tests.