Twelve runners each run one kilometer in shoe A and one kilometer in shoe B, in random order, and both times are recorded for each runner. What design is this?

A teacher randomly assigns 28 students to use app A and 30 different students to use app B, then compares exam scores. What design is this?

In 18 twin pairs, one twin is randomly assigned plan A and the other plan B, and cholesterol change is measured. What design is this?

A clinic records each patient's blood pressure before and after a 6-week exercise program. What design is this?

A survey compares study hours for a random sample of 40 freshmen and a separate random sample of 35 seniors. What design is this?

A farm randomly assigns 20 plots to fertilizer A and 20 different plots to fertilizer B, then records yield in kilograms. What design is this?

In town 1, 96 of 240 households compost; in town 2, 84 of 280 households compost. What is the difference in sample proportions, town 1 minus town 2, rounded to three decimals?

School A has 45 of 150 students in band; school B has 70 of 200 students in band. For a two-proportion z test with H0: pA = pB, what pooled proportion is used?

Group A has 80 successes in 200 trials and group B has 90 successes in 300 trials. For a two-proportion z test with H0: pA = pB, what is the pooled standard error, rounded to three decimals?

Clinic 1 had 30 of 100 patients recover; clinic 2 had 42 of 120 recover. What 95% confidence interval for p1 - p2 uses the unpooled standard error, rounded to three decimals?

Sample A has 90 successes in 150 trials; sample B has 66 successes in 165 trials. For H0: pA = pB, what z statistic for pA - pB is found, rounded to two decimals?

A test of p_new - p_old > 0 gives p-value 0.018 at the 0.05 level. What conclusion is justified?

Group A has mean 18.4 kg and group B has mean 16.9 kg. What is the difference in sample means, A minus B?

Group A has n 25 and s 4.0 minutes; group B has n 16 and s 3.0 minutes. What is the standard error of x-barA - x-barB, rounded to two decimals?

Group A has n 20, x-bar 74, and s 6 points; group B has n 18, x-bar 70, and s 8 points. What two-sample t statistic for A minus B is found, rounded to two decimals?

For a conservative two-sample t test with sample sizes 14 and 19, what degrees of freedom are used?

Class A has n 36, x-bar 52.1, s 9.0; class B has n 36, x-bar 48.5, s 7.2. Using critical value 2.03, what 95% CI for muA - muB is closest?

A two-sample t test comparing mean plant heights gives p-value 0.214 at the 0.05 level. What decision is correct?

Use the output block for a two-sample t test comparing greenhouse benches. At the 0.05 level, what is the decision?

Use the two-proportion output block for the clinic survey. What p-value should be compared with alpha?

Use the two-sample interval output comparing package masses. What point estimate of mu1 - mu2 is shown?

Use the output block for a two-sample t test of mean wait times. What degrees of freedom are reported?

Use the two-proportion output comparing recycling rates. What test statistic is reported?

In a two-way table, one cell is in a row totaling 50 and a column totaling 36, with grand total 120. What is the expected count for that cell?

For a two-proportion z test, group 1 has 12 successes and 88 failures; group 2 has 9 successes and 111 failures. What large-count condition statement is correct?

A chi-square test has expected counts 4.6, 7.2, 8.8, 5.1, 9.4, and 10.9. What condition fails?

Use the commuting table. For a chi-square test, what is the expected count for Grade 9 and Bike?

A goodness-of-fit test sorts 64 bottles equally into 4 label colors. What expected count is in each color, and does it meet the expected-count condition?

A cafeteria chi-square survey used volunteers, and all expected counts are at least 5. Which condition is still not satisfied?

A packet claims candies come in three colors in the ratio 2 to 3 to 5. In a goodness-of-fit test, how many degrees of freedom are used?

A seed mix claims flower colors occur in the ratio 1 to 2 to 2. If 75 flowers are checked, what expected counts are used for the three colors?

For a goodness-of-fit test, observed counts are 18, 32, 50 and expected counts are 20, 30, 50. What chi-squared statistic is found, rounded to three decimals?

A goodness-of-fit test for a snack company's flavor distribution gives p-value 0.012 at the 0.05 level. What conclusion is correct?

A goodness-of-fit test checks whether a six-sided die is fair. What hypotheses match this test?

A chi-square test for independence uses a table with 3 rows and 4 columns. How many degrees of freedom are used?

A chi-square test for independence between grade level and lunch choice gives chi-squared 18.2 and p-value 0.033 at the 0.05 level. What conclusion is justified?

In a chi-square test for independence, a cell has observed count 18 and expected count 12. What is that cell's contribution to chi-squared?

One random sample of students is classified by grade level and lunch choice. What procedure tests whether the two categorical variables are associated?

A chi-square test for independence between club membership and class year gives p-value 0.41 at the 0.05 level. What conclusion is correct?

A random observational survey of students finds a significant association between activity level and sleep category, with p-value 0.004. What scope of conclusion is valid?