Reject the null hypothesis ifP is "small".
1. We need to construct a null hypothesis  an expectation  which the experiment was designed to test. For example:
Support or Reject Null Hypothesis
A test statistic is a standardized value that is calculated from sample data during a hypothesis test. You can use test statistics to determine whether to reject the null hypothesis. The test statistic compares your data with what is expected under the null hypothesis. The test statistic is used to calculate the pvalue.
State the null hypothesis. When you state the null hypothesis, you also have to state the alternate hypothesis. Sometimes it is easier to state the alternate hypothesis first, because that’s the researcher’s thoughts about the experiment. (opens in a new window).
Null hypothesis: μ = 72 Alternative hypothesis: μ ≠72
Notice that the top part of the statistic is the difference between the sample mean and the null hypothesis. The bottom part of the calculation is the standard error of the mean.
When the null hypothesis is false this variance is relatively largeand by comparing it with the withinsample variance
we can tell statistically whether H_{0} is true or not.
Null hypothesis: μ = 72 Alternative hypothesis: μ ≠72
When testing hypotheses about a mean or mean difference, a tdistribution is used to find the pvalue. This is a close cousin to the normal curve. TDistributions are indexed by a quantity called degrees of freedom, calculated as df = n – 1 for the situation involving a test of one mean or test of mean difference.
When testing hypotheses about a mean or mean difference, a tdistribution is used to find the pvalue. This is a close cousin to the normal curve. TDistributions are indexed by a quantity called degrees of freedom, calculated as df = n – 1 for the situation involving a test of one mean or test of mean difference.
Null hypothesis: μ = 72 Alternative hypothesis: μ ≠72

Null hypothesis: μ = 72 Alternative hypothesis: μ ≠72
The final conclusion once the test has been carried out is always given in terms of the null hypothesis.

Null hypothesis: μ = 72 Alternative hypothesis: μ ≠72
The test statistic for examining hypotheses about one population mean difference (i.e. paired data):

Hence the null hypothesis should be rejected.
A onesided hypothesis claims that a parameter is either larger smaller than thevalue given by the null hypothesis.
Null and Alternative Hypothesis  Real Statistics Using Excel
In many statistical tests, you’ll want to either reject or support the . For elementary statistics students, the term can be a tricky term to grasp, partly because the name “null hypothesis” doesn’t make it clear about what the null hypothesis actually is!
How to Determine a pValue When Testing a Null Hypothesis
So what is needed is not just a system of null hypothesis testing but also a system for telling us precisely how large the effects we see in our data really are.
Hypothesis Testing Calculator  Learning about Electronics
where the observed sample mean difference, μ_{0} = value specified in null hypothesis, s_{d} = standard deviation of the differences in the sample measurements and n = sample size. For instance, if we wanted to test for a difference in mean SAT Math and mean SAT Verbal scores, we would random sample subjects, record their SATM and SATV scores in two separate columns, then create a third column that contained the differences between these scores. Then the sample mean and sample standard deviation would be those that were calculated on this column of differences.
Hypothesis Test Example of Calculating Probability
where the observed sample mean difference, μ_{0} = value specified in null hypothesis, s_{d} = standard deviation of the differences in the sample measurements and n = sample size. For instance, if we wanted to test for a difference in mean SAT Math and mean SAT Verbal scores, we would random sample subjects, record their SATM and SATV scores in two separate columns, then create a third column that contained the differences between these scores. Then the sample mean and sample standard deviation would be those that were calculated on this column of differences.
so we do not reject the null hypothesis.
The null hypothesis can be thought of as a nullifiable hypothesis. That means you can nullify it, or reject it. What happens if you reject the null hypothesis? It gets replaced with the which is what you think might actually be true about a situation. For example, let’s say you think that a certain drug might be responsible for a spate of recent heart attacks. The drug company thinks the drug is safe. The null hypothesis is always the accepted hypothesis; in this example, the drug is on the market, people are using it, and it’s generally accepted to be safe. Therefore, the null hypothesis is that the drug is safe. The alternate hypothesis — the one you want to replace the null hypothesis, is that the drug isn’t safe. Rejecting the null hypothesis in this case means that you will have to prove that the drug is not safe.
How do you calculate a null hypothesis
Pulse rates for n = 35 women are available. Here are Minitab results for our hypothesis test. The Minitab process is simply go to Stat > Basic Statistics and select 1Sample t. Select the radio button for Summarized data and enter the values of the sample size, sample mean, and sample standard deviation. Next select the checkbox for Perform Hypothesis Test and enter the hypothesized μ_{o} value. Finally, the default alternative is "not equal". To select a different alternative click Options and select the proper option from the drop down list next to Alternative.