In a recent study of the prevalence of sexually transmitted diseases, a simple random sample of 35,000 Americans were selected and it was found that 20.1% reported having at least one STD. A hypothesis test for a difference from the expected 20% was found to be highly significant, though the difference is quite small. The explanation is that O All of the above O the sample size is very large. O the value of 20.1% is large compared to the hypothesized value of 20%. O it was an aberrant sample.

A news article that you read stated that 52% of voters prefer the Democratic candidate. You think that the actual percent is larger. 149 of the 266 voters that you surveyed said that they prefer the Democratic candidate. What can be concluded at the 0.05 level of significance? For this study, we should use Select an answer t-test for a population mean z-test for a population proportion  The null and alternative hypotheses would be:     Ho: ? p μ  Select an answer ≤ = < ≥ ≠ >   (please enter a decimal)    H1: ? p μ  Select an answer > ≥ ≤ = < ≠   (Please enter a decimal) The test statistic ? z t  =  (please show your answer to 3 decimal places.)

Suppose a 95% confidence interval for the difference in test scores between Class 1 and Class 2 (in that order) is the following: 9 +/− 2. These results were based on independent samples of size 100 from each class. Now suppose you switch the order of Class 1 and Class 2 in your analysis but keep the data labeled correctly in terms of which class they came from. Which of the following statements is false? A) You can't do it this way. You'll get negative numbers for the difference in the means and/or negative numbers for the standard error. B) You are confident that the average for Class 2 is 7 to 11 points lower than for Class 1.    C) You are still confident that the classes have significantly different mean scores. D) Your 95% confidence interval will now be entirely negative: from −7 to −11.

A preliminary study regarding the number of AIDS cases reported for Santa Clara County, California is broken down by race in the table below. White Hispanic Black Asian/Pacific Islander TOTAL Race White Hispanic Black Conduct a chi-square test for goodness-of-fit to determine whether or not the occurrence of AIDS cases is consistent with the race distribution of Santa Clara County. Cases Choose the correct null and alternative hypotheses: O Ho: The distribution of AIDS cases is different from the race distribution in Santa Clara County. Ha: The distribution of AIDS cases is consistent with the race distribution in Santa Clara County. TOTAL 22 Ho: The distribution of AIDS cases is consistent with the race distribution in Santa Clara County. Ha : The distribution of AIDS cases is different from the race distribution in Santa Clara County. Race Asian/Pacific Islander 14 ▼ Part 2 of 4 The population distribution of Santa Clara County by race is provided in the table below. Use these…

In 1945, an organization asked 1480 randomly sampled American citizens, "Do you think we can develop a way to protect ourselves from atomic bombs in case others tried to use them against us?" with 779 responding yes. Did a majority of the citizens feel the country could develop a way to protect itself from atomic bombs in 1945? Use the a = 0.1 level of significance. What are the null and alternative hypotheses? Ho: p versus H,:p %3D > (Type integers or decimals.)