1. A 2001 study asked 1,924 male and 3,666 female undergraduate college students their favorite color. A 95% confidence interval for the difference between the proportions of males and females whose favorite color is black, pmale - P female was calculated to be (0.02, 0.06). Based on this information, determine if the following statements are true or false.
a. We are 95% confident that the true proportion of males whose favorite color is black is 2% lower to 6% higher than the true proportion of females whose favorite color is black.
b. We are 95% confident that the true proportion of males whose favorite color is black is 2% to 6% higher than the true proportion of females whose favorite color is black.
C. Approximately 95% of random samples will produce 95% confidence intervals that include the true difference between the population proportions of males and females whose favorite color is black.
d. The 95% confidence interval for P female - Pmale cannot be calculated with only the information given in this exercise.
A. False, it would be the pmale P female confidence interval times -1
B. True

A Washington Post article from 2009 reported that "support for a government-run health care plan to compete with private insurers has rebounded from its summertime lows and wins clear majority support from the public." More specifically, 70 percent of Democrats back the plan, while almost nine in 10 Republicans oppose it. Independents divide 52 percent in favor of and 42 percent against the legislation. 6% responded with "other". There were 820 Democrats, 566 Republicans and 783 Independents surveyed. Round all results to 4 decimal places.
a. Calculate a 95% confidence interval for the difference between PDemocrat PIndependent . We have already checked conditions for you.
Lower:
Upper:
b. True or false: If we had picked a random Democrat and a random Independent at the time of this poll, it is more likely that the Democrat would support the public option than the Independent.

A package delivery service wants to compare the proportion of on-time deliveries for two of its major service areas. In City A, 315 out of a random sample of 379 deliveries were on time. A random sample of 278 deliveries in City B showed that 211 were on time.
1. Calculate the difference in the sample proportion for the delivery times in the two cities.
PCityA - PCityB =
2. What are the correct hypotheses for conducting a hypothesis test to determine whether the proportion of deliveries that are on time in City A is different from than the proportion in City B?
A. H0 : PA = PB, HA : PA > PB
B. H0 : PA = PB, HA : PA + PB
C. H0 : PA = PB, HA : PA PB
3. Calculate the pooled estimate of the sample proportion.
p =
4. Is the success-failure condition met for this scenario?
A. Yes
B. No
5. Calculate the test statistic for this hypothesis test.
6. Calculate the p-value for this hypothesis test.
p-value =
7. Based on the p-value, we have:
A. some evidence
B. little evidence
c. strong evidence
D. very strong evidence
E. extremely strong evidence that the null model is not a good fit for our observed data.
8. Compute a 95% confidence interval for the difference
p CityA PCityB-
( : )

1. A 2001 study asked 1,924 male and 3,666 female undergraduate col...