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6.41 Open source textbook: A professor using an open source introductory statistics book predicts that 60% of the students will purchase a hard copy of the book, 25% will print it out from the web, and 15% will read it online. At the end of the semester he asks his students to complete a survey where they indicate what format of the book they used. Of the 126 students, 71 said they bought a hard copy of the book, 30 said they printed it out from the web, and 25 said they read it online. (a) State the hypotheses for testing if the professor's predictions were inaccurate. Ho: PBuy = .6, PPrint=.25, POnline=.15 Ha: all of the claimed probabilities are different Ho: PBuy = .6, PPrint=.25, POnline=.15 Ha: at least one of the claimed probabilities is different Ho: PBuy = .6, PPrint=.25, POnline=.15 Ha: at least one of the claimed probabilities is zero (b) How many students did the professor expect to buy the book, print the book, and read the book exclusively online? (please do not round) Observed Expected Buy Hard Copy 71 Print Out 30 Read Online 25 (c) Calculate the chi-squared statistic, the degrees of freedom associated with it, and the p-value. The value of the test-statistic is: (please round to two decimal places) The degrees of freedom associated with this test are: (d) Calculate the p-value. Based on this, what is the conclusion of the hypothesis test? Since p > ? we reject the null hypothesis and accept the alternative Since p > ? we accept the null hypothesis Since p ? ? we reject the null hypothesis and accept the alternative Since p > ? we do not have enough evidence to reject the null hypothesis Since p ? ? we fail to reject the null hypothesis Interpret your conclusion in this context. The data provide sufficient evidence to claim that the actual distribution differs from what the professor expected The data do not provide sufficient evidence to claim that the actual distribution differs from what the professor expected

6.41 Open source textbook: A professor using an open source introductory statistics book predicts that 60% of the students will purchase a hard copy of the book, 25% will print it out from the web, and 15% will read it online. At the end of the semester he asks his students to complete a survey where they indicate what format of the book they used. Of the 126 students, 71 said they bought a hard copy of the book, 30 said they printed it out from the web, and 25 said they read it online.
(a) State the hypotheses for testing if the professor's predictions were inaccurate.
Ho: PBuy = .6, PPrint=.25, POnline=.15
Ha: all of the claimed probabilities are different
Ho: PBuy = .6, PPrint=.25, POnline=.15
Ha: at least one of the claimed probabilities is different
Ho: PBuy = .6, PPrint=.25, POnline=.15
Ha: at least one of the claimed probabilities is zero
(b) How many students did the professor expect to buy the book, print the book, and read the book exclusively online? (please do not round)
Observed Expected
Buy Hard Copy 71
Print Out 30
Read Online 25
(c) Calculate the chi-squared statistic, the degrees of freedom associated with it, and the p-value.
The value of the test-statistic is: (please round to two decimal places) The degrees
of freedom associated with this test are: (d) Calculate the p-value. Based on this,
what is the conclusion of the hypothesis test?
Since p > ? we reject the null hypothesis and accept the alternative
Since p > ? we accept the null hypothesis
Since p ? ? we reject the null hypothesis and accept the alternative
Since p > ? we do not have enough evidence to reject the null hypothesis
Since p ? ? we fail to reject the null hypothesis
Interpret your conclusion in this context.
The data provide sufficient evidence to claim that the actual distribution differs from what the professor expected
The data do not provide sufficient evidence to claim that the actual distribution differs from what the professor expected

Added by Jack H.

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