Respuesta :
Answer: option B
Step-by-step explanation: at alpha level of 5% for a two tailed test, the critical value is +1.96 and -1.96
At alpha level of 1% for a two tailed test, the critical value is +2.576 and -2.576
Relating z = 2.77 with these critical values, we can see that at 5% level of significance, z = 2.77 is greater than +1.96 which falls in the rejection region.
Also at 1% level of significance, we can see that z = 2.77 is greater than 2.576 which also falls in the rejection region.
Answer:
Option b: The researcher should reject the null hypothesis with either a = 0.05 or a = 0.01.
Step-by-step explanation:
We are given that a researcher administers a treatment to a sample of n = 25 participants and uses a hypothesis test to evaluate the effect of the treatment. The hypothesis test produces a z-score of z = 2.77.
Also, it is assumed that the researcher is using a two-tailed test.
Now, firstly we will find the critical value of z at significance level [tex](\alpha)[/tex] 0.05 and 0.01.
Our decision rule will be ;
- If the value of z score is more than the critical values of z, then we will reject null hypothesis.
- If the value of z score is less than the critical values of z, then we will not reject null hypothesis.
So, at 0.05 significance level z table gives critical value of 1.96.
and at 0.01 significance level z table gives critical value of 2.5758.
As we can clearly see that our z score is more than both the critical values of z at significance level 0.05 and 0.01 so we have sufficient evidence to reject null hypothesis at both significance level.
Hence, the researcher should reject the null hypothesis with either a = 0.05 or a = 0.01.