Question

Elementary Statistics Vernh X Estimate the Difference be × ·E Estimate the Difference be Estimate the Differe u/jcourse/a2/rest/assessement/deliver?context 3db2666b0a0001dc655430fb9dec98288attempt-2 Countdown: Days:-o Time:-03:32:59 Question2 In March 2015, the Public Policy Institute of California (PPIC) surveyed 7,525 Select one answer likely voters living in California. In the survey, respondents were asked about o points global warming. PPIC results show that 47% of adults age 55 and older view global warming as a serious problem, and 65% of adults age 18 to 34 view global warming as a serous problem. PPIC researchers are interested in the difference in proportions of adults age 55 and over and adults age 18 to 34. The standard error for the difference in proportions is o.o1n. Researchers want to decrease the margin of error by adjusting the confidence level. Which confidence interval will have the smallest margin of error (MOE)? A. @ 90% confidence interval B. 95% confidence interval C. @ 99% confidence interval Question 3 In March 2015, the Public Policy Institute of California (PPIC) surveyed 7525 Select one anmeer likely voters living in California. This is the 148th PPIC research poll, and is so points part of a survey series that started in 1998. PPIC researchers find that 3266 survey participants are registered Democrats and 2137 survey participants are registered Republicans. PPIC is interested in the difference in approval rate for the governor between registered Democrats and registered Republicans in California

Answer 1

Confidence interval = Mean $\small \pm$ Z* x Standard error

Here, Mean and Standard error are constant

Critical value z* varies with confidence level

As confidence level increases, Z* value increases. Smallest Z* value among the given three is corresponding to 90% confidence level. hence, 90% confidence interval will have the smallest margin of error.

Ans: A. 90% confidence interval