Experiment 1: You believe that caffeine can improve the capacity of short-term memory (STM). It is widely known that STM capacity 7 items (m=7)on average with a standard deviation of 2 items (s=2). You randomly sampled n=8 participants and have then drink a large quantity of coffee. Fifteen minutes later you administer a STM test to each participant and measure the number of items remembered. The data are shown below. Use these data to answer the following questions. Excel should be used to obtain the sample mean, standard deviation and standard error. Perform a 2-tailed z-test with a=0.05 to determine if caffeine influences memory. Number of items Participant 1 2 7 4 7 6 17 7 8 9 3.

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Confidence Intervals

When we calculate intervals in probability and statistics, it can be simply termed as finding out a confidence interval. The confidence interval is usually calculated from the data set which is observed. The value of the parameter that needs to be calculated is present here only.