Many people take ginkgo supplements advertised to improve memory. Are these over-the-counter supplements effective? In a study reported in the paper “Ginkgo for memory Enhancement” (Journal of the American Medical Association), elderly adults were assigned at random to either a treatment or a control group. The 104 participants who were assigned to the treatment group took 40 mg of ginkgo three times a day for six weeks. The 115 participants assigned to the control group took a placebo pill three times a day for six weeks. At the end of six weeks, the Wechsler Memory Scale (a test of short-term memory) was administered. Higher scores indicate better memory function. Summary values are given in the following table. TABLE ATTACHED AS PICTURE Based on these results, we want to find whether there is evidence that taking 40 mg of ginkgo three times a day is effective in increasing mean performance on the Wechsler Memory Scale. A) Calculate the test statistic for the test above. (round test statistic to 2 decimal places) __________________ B) What is the cutoff value for the rejection region? Use significance level 0.05. (round to 2 decimal places) _________________ C) What's your decision on the hypothesis test above? Use significance level 0.05. __________________ (type Reject for Reject Ho, type FTR for Fail to Reject Ho)
Addition Rule of Probability
It simply refers to the likelihood of an event taking place whenever the occurrence of an event is uncertain. The probability of a single event can be calculated by dividing the number of successful trials of that event by the total number of trials.
Expected Value
When a large number of trials are performed for any random variable ‘X’, the predicted result is most likely the mean of all the outcomes for the random variable and it is known as expected value also known as expectation. The expected value, also known as the expectation, is denoted by: E(X).
Probability Distributions
Understanding probability is necessary to know the probability distributions. In statistics, probability is how the uncertainty of an event is measured. This event can be anything. The most common examples include tossing a coin, rolling a die, or choosing a card. Each of these events has multiple possibilities. Every such possibility is measured with the help of probability. To be more precise, the probability is used for calculating the occurrence of events that may or may not happen. Probability does not give sure results. Unless the probability of any event is 1, the different outcomes may or may not happen in real life, regardless of how less or how more their probability is.
Basic Probability
The simple definition of probability it is a chance of the occurrence of an event. It is defined in numerical form and the probability value is between 0 to 1. The probability value 0 indicates that there is no chance of that event occurring and the probability value 1 indicates that the event will occur. Sum of the probability value must be 1. The probability value is never a negative number. If it happens, then recheck the calculation.
Many people take ginkgo supplements advertised to improve memory. Are these over-the-counter supplements effective? In a study reported in the paper “Ginkgo for memory Enhancement” (Journal of the American Medical Association), elderly adults were assigned at random to either a treatment or a control group. The 104 participants who were assigned to the treatment group took 40 mg of ginkgo three times a day for six weeks. The 115 participants assigned to the control group took a placebo pill three times a day for six weeks. At the end of six weeks, the Wechsler Memory Scale (a test of short-term memory) was administered. Higher scores indicate better memory
TABLE ATTACHED AS PICTURE
Based on these results, we want to find whether there is evidence that taking 40 mg of ginkgo three times a day is effective in increasing mean performance on the Wechsler Memory Scale.
A) Calculate the test statistic for the test above. (round test statistic to 2 decimal places) __________________
B) What is the cutoff value for the rejection region? Use significance level 0.05. (round to 2 decimal places) _________________
C) What's your decision on the hypothesis test above? Use significance level 0.05. __________________
(type Reject for Reject Ho, type FTR for Fail to Reject Ho)
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