## Psy 315 Answer solutions for the assignment

Solution for assignment

When a result is not extreme enough to reject the null hypothesis, explain why it is wrong to conclude that your result supports the null hypothesis.

Solution:

There are two approaches for answering this question. First approach is the critical value approach and second is p-value approach. Because we use these two values for rejecting or do not rejecting the null hypothesis. That is, decision is based on these two values. We compare critical value with the test statistic value and then take decision regarding the null hypothesis. Also, we compare p-value with the level of significance alpha value and then we decide whether reject or do not reject the null hypothesis. Let us see the two answers for above questions in detail.

The result is not extreme enough to reject the null hypothesis, when test statistical value is less than the critical value. For any type of hypothesis test, we first establish the null and alternative hypothesis. In so many conditions, our alternative hypothesis is nothing but the claim which we have to test by using the available data. For this test we find the test statistic value. We find the critical value according to given confidence level. Then we use the decision rule for rejecting or do not rejecting the null hypothesis. This decision rule is given as below:

Reject the null hypothesis if the test statistic value is greater than critical value. Do not reject the null hypothesis if the critical value is greater than the test statistic value.

The result is not extreme enough to reject the null hypothesis, when the p-value is greater than the level of significance alpha value. We either use the critical value approach or p-value approach for taking decision regarding null hypothesis. The decision rule for p-value approach is given as below:

Reject the null hypothesis if the p-value is less than level of significance alpha value. We do not reject the null hypothesis if the p-value is greater than the level of significance alpha value. Remember that p-value is nothing but the probability of rejection area under the curve.

4.The general population (Population 2) has a mean of 30 and a standard deviation of 5, and the cutoff Z score for significance in a study involving one participants is 1.96. If the raw score obtained by the participant is 45, what decisions should be made about the null and research hypothesis?

z = (X-Mu)/SD
z = (45-30)/5 = + 3
Since the z-score (+3) of the concerned raw score of the participant > 1.96, the null hypothesis will be rejected. In other words, it can be said that there is sufficient evidence to reject the null hypothesis
The alternative hypothesis can be accepted
It can be inferred that there is significant difference between the raw score and population mean

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