The One Sample Z Test A large school district claims that 80% of the children are from low-income families. 130 children from the district are chosen to participate in a community project. Of the 130 only 72% are from low-income families. The children were supposed to be randomly selected. Do you think they really were? a. The null hypothesis is that the children were randomly chosen. This translates into drawing 130 times Computer's answer now shown above. You are correct. Your receipt no. is 154-58 (? Previous Tries at random Incorrect with replacement Correct: without replacement Computer's answer now shown above. You are correct. Your receipt no. is 154-9674 (? Previous Tries from a null box that contains b. Incorrect 130 tickets, 72% marked "1" and 28% marked "0" Correct: Thousands of tickets, 80% marked "1" and 20% marked "0" Incorrect Thousands of tickets marked either "1" or "0", but the exact percentages of each are unknown and estimated from our sample. Incorrect 5 tickets, 1 marked "1" and 4 marked "0" Computer's answer now shown above. You are correct. Your receipt no. is 154-435 (? Previous Tries c. What is the expected value of the percent of 1's in the draws? (Don't type in the % sign) 80 % Computer's answer now shown above. You are correct. Your receipt no. is 154-9042 (? Previous Tries 1. What is the SD of the null box? (Note: We don't have to estimate the SD of the box from the sample SD because we can compute it directly from the percent of 1's in the null box. This is why we never use a t-test for problems that can be translated into 0-1 boxes. ) 0.4 Computer's answer now shown above. You are correct. Your receipt no. is 154-1540 (? Previous Triese. What is the standard error of the % of 1's in the draws? (Round to 2 decimal places. ) 3.51 % Computer's answer now shown above. Incorrect. Tries 3/3 Previous Tries f. What is the value of the test statistic z? (Round answer to 2 decimal places.) -2.28 Computer's answer now shown above. You are correct. Your receipt no. is 154-6913 (? Previous Tries g. What is the p-value? Click here to view the normal table 2.26 % Submit Answer You have entered that answer before | Incorrect. Tries 2/3 Previous Tries h. What do you conclude? Incorrect We cannot reject the null, it's plausible the children were randomly chosen. Correct: There is very strong evidence to reject the null, and conclude that the children were not randomly chosen. Computer's answer now shown above. You are correct. Your receipt no. is 154-9611 (?) Previous Tries