Biochemical Oxygen Demand Hypothesis Testing Essay

Biochemical oxygen Demand Hypothesis Testing - Essay ExampleRejection of the null theory leads to the acceptance of the selection hypothesis. The alternative hypothesis states that there is a difference between the procedures. It is de noned by H1. Assuming that the upstream BOD and downstream BOD are normally distributed, we test using import level of 0.05 whether BOD increases at the downstream. The signifi crapperce level of a statistical hypothesis test is a fixed probability of rejecting the null hypothesis H0 when it is in fact true. It is called a type I error and is set by the investigator in relation to the consequences of such an error. We want to make the significance level as small as practical in order to protect the null hypothesis and to prevent, as far as possible, the investigator from unknowingly making false claims. Test Statistic It is the random variable X whose value is tested to arrive at a decision. The Central Limit Theorem states that for large sample si zes (n 30) drawn randomly from a population, the distribution of the message of those samples will approximate normality, even when the data in the parent population are not distributed normally. A z statistic is usually used for large sample sizes (n 30), but often large samples are not easy to obtain, in which case the t-distribution can be used. The population standard deviation s is estimated by the sample standard deviation,The observed t value is calculated from the sample used. Testing of means can be accomplished when the data are in the form of paired observations. We compute for the confidence musical interval of d - u in the situation with paired observations is based on the random variableWhere and are random variables representing the sample mean and standard deviations of the differences of the observations in the experimental units. This two-sample occupation is essentially reduced to a one-sample problem by using the computed difference d1, d2, d3 dn. Thus the hyp othesis reduces to Ho =do