Psychology and Statistics

Rosalind Dymond Cartwright, her  groundbreaking research concluded dreaming is important for mental health because it helps people organize thoughts and deal with worries and emotions.

The pdf(such as in binompdf) stands for probability density function . It is a function that tells you the probability of certain events occurring. EXAMPLE 1 In a particular population, the probability that people test positive for the COVID-19 virus infection is 0.1, therefore the probability of having a negative result is 0.9. Four patients from this population test for COVID-19, what is the probability that the results of the four are all positive? Answer:   In how many patterns can all four results be positive? Only one, i.e. A,B,C,D are all positive? Patient Test result p A + 0.1 B + 0.1 C + 0.1 D + 0.1 Independence check: whether one person’s result is positive or negative is not influenced by any other person’s result, we can multiply individual probabilities of being positive to find the probability that all the...

Review on H ypothesis T esting The objective of the hypothesis testing procedure is to find out whether we can reject the null hypothesis. To reject or not to reject the null hypothesis is a decision made by the researcher. This decision must be based upon an explicitly stated criterion. One has to specify exactly under what conditions that one is willing to reject the null hypothesis. The criterion comes from the research result. It is based upon a critical statistical information from the sample observed. It could be an individual score (if there is one person in the sample, N = 1) or a mean (if there are multiple persons in the sample, N > 1).   One wants to create a dilemma between the sample statistic (i.e., the observation) and the null hypothesis. This dilemma or conflict can be represented in terms of probability or likelihood. The researcher wants to show that if the null hypothesis were true, a sample statistic (score or mean) as extreme as the one observed would be...