Question

The following data represent the discrete probability distribution for the number of stars that reviewers have a first edition statistics reference book. Stars 5 4 3 2 1 Probability 25% 35% 20% 10% 10% The second edition of this reference book has been released and a random sample of people that have purchased the book has been collected with the following results. Stars 5 4 3 2 1 Frequency 28 28 13 6 5 The publisher would like to know if the probability distribution for reviews has changed from the first edition to the second edition using α = 0.025. The expected frequency of three-star reviews is ________.

Answer 1

Explanation:

given that the following data represent the discrete probability distribution for the number of stars that reviewers have a first edition statistics reference book.

Stars 5 4 3 2 1

Probability 25% 35% 20% 10% 10%

H0: Second edition is as per the above probabilities

Ha: atleast one is different from the above probability

(two tailed chi square test)

Alpha = 0.025

Assuming H0 to be true we calculate expected frequencies for total 80

chi square calculatons are shown below

df = 4

5 4 3 2 1 Total

Observed 28 28 13 6 5 80

Expected 20 28 16 8 8 80

chi square

(O_E)^2/E 3.2 0 0.5625 0.5 1.125 5.3875

p value =0.1455

Since p value >0.025, we accept H0

The expected requency of three-star reviews is ________.16