Ch 11 Chi-Square Tests

11.1 The Chi-Square Distribution

11.2 A Goodness-of-Fit Test

11.3 A Test of Independence or Homogeneity

Question 1 of9 > /'| E State the degrees of freedom to be used when conducting a 2'2 test for each situation, and use a table to fInd the value that your calculated 3'2 value would have to exceed in order to be statistically signicant at the given a level. Round your answers for 12 to 2 decimal places. a)You are checking the fairness ofa 6- sided die, with a = 0.05. I: n n b}You are examiningthe results of an experimentwith4treatments,witha = 0.01. den n c)You are comparing outcomes In 101 different categories with a_ 0.005. I: n n 0.. Question 2 of9 -/'I :: View Policies Current Attempt in Progress Florence thought people would like cheese, pepperoni, and veggie pizza equally. But when she asked 12 friends, 4 said they preferred Cheese, 6 said they preferred pepperoni, and only 2 said they liked veggie. Compute the value of X2- 2 = Question 3 of9 _/1 1: View Policies Current Attempt in Progress Using Table VI in Appendix C, nd to 3 decimal places the value of g2 for 5 degrees of freedom and (a) 0.025 area in the right tail of the chi-square distribution curve. 12= (b) 0.05 area in the left tail of the chi-square distribution curve. 12= Question 4 of 9 I \"\"H. 4 up\" 000 One of the products produced by Branco Food Company is All-Bran Cereal, which competes with three other brands of similar all-bran cereals. The compa ny's research ofce wants to investigate if the percentage of people who consume all-bran cereal is the same for each of these four brands. Let us denote the four brands of cereal by ABC, and D. A sample of 700 persons who consume all-bran cereal was taken, and they were asked which brand they most often consume. Of the respondents, 162 said they usually consume Brand A, 184 consume Brand 8,191 consume Brand C, and 163 consume Brand D. Does the sample provide enough evidence to reject the null hypothesis that the percentage of people who consume all-bran cereal is the same for all four brands? Usea = 0.05. Find the value of the test statistic 32. Round your answer to three decimal places. 22= on .0. Question 6 of 9 -/'I 5: Over the past three years, Art's Supermarket has observed the following distribution of modes of payment in the express lines: cash (C) 47%, checks (CK) 15%, credit or debit cards (D) 22%, and other (N) 16%. In an effort to make express checkout more efficient, Art's has just begun offering a 1% discount for cash payment in the express checkout line. The following table lists the frequency distribution of the modes of payment for a sample of 500 express line customers after the discount went into effect. Ill Numberofcustomers 324 63 66 47 Test at the 10% signicance level whether the distribution of modes of payment in the express checkout line changed after the discount went into effect. 0 The distribution of modes of payment in the express checkout line did not change after the discount went into effect. 0 The distribution of modes of payment in the express checkout line 0 changed after the discount went into effect. Question 7 of 9 - /1 . .. Home Mail Corporation sells products by mail. The company's management wants to find out if the number of orders received at the company's office on each of the five days of the week is the same. The company took a sample of 450 orders received during a four-week period. The following table lists the frequency distribution for these orders by the day of the week. Day of the week Mon Tue Wed Thu Fri Number of orders received 90 96 81 89 94 Test at the 5% significance level whether the null hypothesis that the orders are evenly distributed over all days of the week is true. O The orders are not evenly distributed over all days of the week. O The orders are evenly distributed over all days of the week.Question 8 of 9 - /1 ... State the degrees of freedom to be used when conducting a x2 test for each situation. a) There are three samples classified according to five categories. df = b) School-age children, and elderly adults, are each asked if they use the internet never, sometimes, or often. df = i c) Eighteen different strains of bacteria are tested for resistance to an antibiotic, and classified as resistant or non-resistant. df = iQuestion 9 of 9