A researcher is conducting a study to examine the effect of an intervention on t

Question

A researcher is conducting a study to examine the effect of an intervention on test anxiety. The research calculations the statistical power of her research study before collecting data. She finds that if she uses a two-tailed hypothesis test with alpha .05 and a sample of 20 participants per group, her power to detect a difference between her treatment and control condition is .52. Based on this information, what should the researcher do to improve power.

include another level of the independent variable

increase the sample size of her study

remove outliers from her data

lower the alpha level for her study

include another level of the independent variable

increase the sample size of her study

remove outliers from her data

lower the alpha level for her study

Explanation / Answer

(i) Obiously we can increase power by increasing sample size of our study beacause by increasing the sample size we can get more information about population so our power increases.

(ii) By removing outliers our standard deviation decreases so our power increases.

(iii) As our significance level or alpha decreases our type II error increases so power decreases(power =1 - type II error). so to increases our power we should increase the level of significance.

So as you have not started the data collection so you should take more than 20 sample to increase your power.

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