Nine experts rated two brands of coffee in a taste-testing experiment. A rating on a 7-point scale (1 = extremely unpleasing, 7 = extremely pleasing) is given for each of four characteristics: taste, aroma, richness, and acidity. The accompanying data table contains the ratings accumulated over all four characteristics. Complete parts (a) through (d) below. E Click the icon to view the data table. Expert С.С. Brand A Brand B a. At the 0.05 level of significance, is there evidence of a difference in the mean ratings between the two brands? 24 26 Let u, be the mean rating for brand A and uz be the mean rating for brand B. Determine the null and alternative hypotheses for this test. S.E. 23 23 E.G B.I. 17 19 O A. Ho: Ho #0 (where Ho "P -P2) H: HD =0 O B. Ho: Ho =0 (where Ho = , -P2) H,: Ho #0 22 25 OC. Ho: Ho s0 (where Ho "H1 -P2) С.М. 22 25 O D. Ho: Ho 20 (where Ho "H4 - P2) H: Hp <0 H: Ho >0 C.N. 25 26 G.N. 26 25 The test statistic is tSTAT = R.M. 24 25 (Type an integer or a decimal. Round to two decimal places as needed.) P.V. 23 25 The critical value(s) is(are) (Type integers or decimals. Round to two decimal places as needed. Use a comma to separate answers as needed.) does not fall between reject sufficient Since the test statistic or the critical value(s), or Ho. There is or evidence to conclude that the mean ratings are different between the two brands. falls between do not reject insufficient b. What assumption is necessary about the population distribution in order to perform this test? A. It must be assumed that the distribution of the differences between the measurements is approximately uniform. B. It must be assumed that the distribution of the differences between the measurements is approximately normal. C. It must be assumed that the distribution of the differences between the measurements is skewed. c. Determine the p-value in (a) and interpret its meaning. The test statistic gives a p-value of (Type an integer or a decimal. Round to three decimal places as needed.) Interpret the meaning of the p-value in (a). Choose the correct answer below. A. The p-value is the probability of obtaining a sample mean difference less extreme than this one if the population mean ratings for the two brands are the same. B. The p-value is the probability of obtaining a sample mean difference at least as extreme as this one if the population mean ratings for the two brands are the same. C. The p-value is the probability of failing to reject the null hypothesis when it is actually false.
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.
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