Five Steps in a Hypothesis Test
Pulse rates for n = 35 women are available. Here are Minitab results for our hypothesis test:
When we evaluate the nullhypothesis, we can make 2 types of errors.
Before moving onto the second step of the hypothesis testing process, we need to take you on a brief detour to explain why you need to run hypothesis testing at all. This is explained next.
Most of the reports arguing for EMT and cancer stemcell correlation focus on the idea that an EMT phenotype drives acancer stem cell microenvironment that is characterized asCD44/CD24 in breast cancer, which isassociated with therapeutic resistance, tumor invasion and poorprognosis (,). As we observed in the current study,HER2 overexpression leading to STAT3 activation resulted inupregulation of CD44 expression. Furthermore, a recent study byOliveras-Ferraros concluded that a mesenchymalCD44/CD24 microenvironment in HER2overexpressed breast cancer was linked to resistance to Herceptintreatment ().
Test the appropriate hypothesis at the 5% level.
The level of statistical significance is often expressed as the so-called p-value. Depending on the statistical test you have chosen, you will calculate a probability (i.e., the p-value) of observing your sample results (or more extreme) given that the null hypothesis is true. Another way of phrasing this is to consider the probability that a difference in a mean score (or other statistic) could have arisen based on the assumption that there really is no difference. Let us consider this statement with respect to our example where we are interested in the difference in mean exam performance between two different teaching methods. If there really is no difference between the two teaching methods in the population (i.e., given that the null hypothesis is true), how likely would it be to see a difference in the mean exam performance between the two teaching methods as large as (or larger than) that which has been observed in your sample?
The alternative hypothesis can bedirectional or non-directional.“Eating oatmeal lowers cholesterol” is a directional hypothesis; “Amountof sleep affects test scores” is non-directional.
Test at ALPHA=.05 the hypothesis that the true weight is 140 lb.
Sarah predicted that her teaching method (independent variable: teaching method), whereby she not only required her students to attend lectures, but also seminars, would have a positive effect (that is, increased) students' performance (dependent variable: exam marks). If an alternative hypothesis has a direction (and this is how you want to test it), the hypothesis is one-tailed. That is, it predicts direction of the effect. If the alternative hypothesis has stated that the effect was expected to be negative, this is also a one-tailed hypothesis.
As such, by taking a hypothesis testing approach, Sarah and Mike want to generalize their results to a population rather than just the students in their sample. However, in order to use hypothesis testing, you need to re-state your research hypothesis as a null and alternative hypothesis. Before you can do this, it is best to consider the process/structure involved in hypothesis testing and what you are measuring. This structure is presented .
type 1 errorBack to Back to 1662-2
Statistical hypothesis testing - Wikipedia
Identify the critical value suitable for conducting a two-tail test of the hypothesis at the 2% level.
Hypothesis | Type I And Type Ii Errors | Hypothesis
The hypothesis test that followed ended with a decision of "reject H(O)".
Hypothesis Tests - Statistics and Probability
Test the null hypothesis that the new ball does not improve a bowler's average at the 5% level of significance.
Test of hypothesis - SlideShare
BT474 wild-type, SKBR3 wild-type and MCF7 wild-typecells were obtained from the American Type Culture Collection(ATCC). They were maintained in a monolayer culture in DMEM/F12(Dulbecco’s modified Eagle’s medium) with 10% fetal bovine serum,2.5% L-glutamine and 0.5% penicillin/streptomycin. The MCF7-HER2(MCF7 cells transfected with HER2) cell line was a generous gift ofDr C. Kent Osborne (Baylor College of Medicine, Houston, TX).MCF7-HER2 cells were maintained in a monolayer culture in DMEM 1Xwith 10% fetal bovine serum, 2.5% L-glutamine, 0.5%penicillin/streptomycin, and G418 (400 g/ml).
How to Plan and Write a Testable Hypothesis - wikiHow
Suppose we conduct an experimentto test whether a new drug is effective in reducing cholesterol, and, afterfollowing our steps for hypothesis testing, we are unable to reject H0.There are 2 reasons this might happen:
Which type of hypothesis cannot be tested? Why does …
In statistics terminology, the students in the study are the sample and the larger group they represent (i.e., all statistics students on a graduate management degree) is called the population. Given that the sample of statistics students in the study are representative of a larger population of statistics students, you can use hypothesis testing to understand whether any differences or effects discovered in the study exist in the population. In layman's terms, hypothesis testing is used to establish whether a research hypothesis extends beyond those individuals examined in a single study.
Hypothesis Testing: Type I or Type II Error - BrainMass
Initially we tested the effect of STAT3 inHER2-positive breast cancer. We wished to determine whether theco-expression of HER2 and ER induced STAT3 phosphorylation, andwhether pSTAT3 promotes stem-like cell phenotype in the breastcancer model. To this end, the basal expression of STAT3 and stemcell markers were examined in various human breast cancer celllines by western blot analysis and real-time PCR. STAT3 wasphosphorylated in MCF7-HER2 cells, but not in MCF7 wild-type(). In addition, STAT3 wasphosphorylated in BT474 as well as at very low level in SKBR3. MCF7wild-type lacks HER2 amplification and SKBR3 lacks ER. This isconsistent with previous data in which MCF7 WT did not typicallyshow phosphorylation of STAT3 (,).Moreover, we found that the stem cell markers, Oct-4 and Sox-2,were expressed in MCF7-HER2 and BT474 cells, but not in MCF7wild-type and SKBR3 ().Real-time PCR analyses confirmed the upregulation of stem cellmarkers in HER2-overexpressing, ER-positive cancer cells (). Our results support thehypothesis that HER2 over-expression and ER positivity promoteSTAT3 phosphorylation and induces the stem cell-like phenotype.
Solved: Hypothesis testing and type, Mathematics
Transcription factor slug, which has been implicatedas a driver for the epithelial-mesenchymal transition (EMT) wasupregulated in MCF7-HER2 cells (), leading us to the hypothesis that, HER2 induced stem cellmarker expression and slug upregulation promoted the EMT phenotypein MCF7 cells. Real-time PCR analyses showed the gene expressionpattern matching with the mesenchymal microenvironment, showingsignificant upregulation in vimentin, slug and concurrentdownregulation of E-cadherin in MCF7-HER2 compared with controlMCF7 wild-type (). In linewith the PCR data, western blot analyses revealed that epithelialmarker E-cadherin was downregulated, while mesenchymal makervimentin was upregulated in HER2 transfected MCF7 cells (). These results indicate that thesequential activations elicited by HER2 amplification converge intothe HER2-pSTAT3-stem cell markers - early EMT characteristics insignal pathways.
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