Statistical Power | What it is | How can we help - Statswork

# Power Calculation - What is statistical power?

##### Our Statswork experts bring the best out of your study. Data leverage is one of the important strategies that the corporate world currently uses to maximize its profits through insights. We as statistical experts help you in providing business and research insights. #### Power Calculation - What is statistical power?

Statistical power means it minimizes the probability of making type II error i.e., It leads to probability of reject a false null hypothesis.

.

where β = Type II error

β=Prob (Accept H0 / when H0 is false) where 0≤ β<1

#### Calculation of Statistical Power

The researchers must have some information before they can do the power and sample size calculation. The information includes previous knowledge about the population parameters and what confidence or significance level is needed in the study. We help you in this critical situation where our expertise suggest you the best technology and guide in the analysis

#### Hand Calculation

Being a statistical analyst expert, we guide you on how to calculate the sample size needed for a study. Given that a researcher or the business decision maker has the null hypothesis that μ=μ0 and alternative hypothesis that μ=μ1≠ μ0, and that the population variance is known as σ2 where 0≤σ2<∞. Also, that the researcher knows that they want to reject the null hypothesis at a significance level of α which gives a corresponding Z valueᵩ, called it Zα/2.

Therefore, the power function will be P{Z> Zα/2 or Z< -Zα/2|μ1}=1-Φ[Zα/2-(μ1-μ0)/(σ/n)]+Φ[-Zα/2-(μ1-μ0)/(σ/n)]. Where α is the level of significance, Zα/2 =Z value corresponding to the level of significance, μ1&μ0 are assumed population parameter (mean value), σ is the population standard deviation, n= sample size. That is a function of the power and sample size given other information known and the researcher can get the corresponding sample size for each power level.