Scientific Hypothesis, Theory, Law Definitions - …

In conclusion, we found that in arrested L1 worms whose parents were grown on plates purine metabolism stops at uric acid, while in arrested L1s whose parents were grown in liquid culture it proceeds one step further and uric acid is converted to allantoin. At present, we do not have a satisfactory explanation for this effect. Finally, we found that there was no significant difference in L1 starvation survival between these two groups of worms.

Hypothesis Test: Difference in Means

Difference between Hypothesis and Theory

Hypothesis vs Hoctaw - What's the difference? | WikiDiff

So, you might get a p-value such as 0.03 (i.e., p = .03). This means that there is a 3% chance of finding a difference as large as (or larger than) the one in your study given that the null hypothesis is true. However, you want to know whether this is "statistically significant". Typically, if there was a 5% or less chance (5 times in 100 or less) that the difference in the mean exam performance between the two teaching methods (or whatever statistic you are using) is as different as observed given the null hypothesis is true, you would reject the null hypothesis and accept the alternative hypothesis. Alternately, if the chance was greater than 5% (5 times in 100 or more), you would fail to reject the null hypothesis and would not accept the alternative hypothesis. As such, in this example where p = .03, we would reject the null hypothesis and accept the alternative hypothesis. We reject it because at a significance level of 0.03 (i.e., less than a 5% chance), the result we obtained could happen too frequently for us to be confident that it was the two teaching methods that had an effect on exam performance.

Difference between Hypothesis and Prediction

If our statistical analysis shows that the significance level is below the cut-off value we have set (e.g., either 0.05 or 0.01), we reject the null hypothesis and accept the alternative hypothesis. Alternatively, if the significance level is above the cut-off value, we fail to reject the null hypothesis and cannot accept the alternative hypothesis. You should note that you cannot accept the null hypothesis, but only find evidence against it.

Hypothesis test for difference of means (video) | Khan …

We profiled mRNA levels in arrested L1 larvae from plate- and liquid culture-grown mothers. We found 145 genes that were different between these two groups by a factor of 3 or more (). Half of them were genes encoding proteins with unknown function or homology. and were overexpressed in L1 progeny from plates compared to liquid culture (3 and 4.1 fold difference). This might indicate that progeny from plates have better ROS protection, while liquid culture progeny are more susceptible to oxidative stress and uric acid acts there as an endogenous antioxidant, resulting in its nonenzymatic oxidation to allantoin. We then compared uric acid and allantoin levels in L1 medium of (), () and N2 whose parents were grown on plates and found no significant difference. We also measured uric acid and allantoin concentrations in L1 medium (both from plates and liquid culture) in the presence of 200 µM epicatechin, an antioxidant that was shown to reduce oxidative stress in adult C. elegans (). Epicatechin had no effect on uric acid and allantoin levels. Overall, these experiments suggest that different levels of oxidative stress may not explain differences in the uric acid/allantoin ratio.

What is the Difference Between a Theory and a Hypothesis?

The null hypothesis is essentially the "devil's advocate" position. That is, it assumes that whatever you are trying to prove did not happen (hint: it usually states that something equals zero). For example, the two different teaching methods did not result in different exam performances (i.e., zero difference). Another example might be that there is no relationship between anxiety and athletic performance (i.e., the slope is zero). The alternative hypothesis states the opposite and is usually the hypothesis you are trying to prove (e.g., the two different teaching methods did result in different exam performances). Initially, you can state these hypotheses in more general terms (e.g., using terms like "effect", "relationship", etc.), as shown below for the teaching methods example:

Hypothesis Testing - Difference in Means - BrainMass

In order to undertake hypothesis testing you need to express your research hypothesis as a null and alternative hypothesis. The null hypothesis and alternative hypothesis are statements regarding the differences or effects that occur in the population. You will use your sample to test which statement (i.e., the null hypothesis or alternative hypothesis) is most likely (although technically, you test the evidence against the null hypothesis). So, with respect to our teaching example, the null and alternative hypothesis will reflect statements about all statistics students on graduate management courses.