Author:
Christine Farr

1. A reporter wishes to estimate the percent of men at a women’s-rights rally. In arandom sample of 1357 people at the rally, he observed 246 men.a. The 246 is the _______ value for the number of men in the sample.Options:1. expected (ii) observedb. The SD of the box is _______ 0.181 0.819 .Options:1. exactly equal to (ii) estimated from the data asc. Find a 95% confidence interval for the percentage of men at the rally.2. In a certain town, there are 4,000 registered voters, of whom 1,000 are Democrats.A survey organization is about to take a random sample of 100 registered voters.a. There is about a 50-50 chance that the percentage of Democrats in thesample will be bigger than _____.b. Find the expected value for the sample percentage,c. Find the standard error for the sample percentage.d. Find the chance that 30% or more of the people in sample are Democrats.e. True or false: If a large sample were taken, the standard error for thesample percentage would have been smaller.3. 900 draws are made at random with replacement from the box:2 4 6a. What is the expected value and SE for the average of 900 draws?b. What is the expected value and SE for the sum of 900 draws?c. If the sum of 900 draws is 3500, is this reasonable?4. A simple random sample of 625 households is surveyed from a city. On theaverage, there are 2.30 persons per sample household with SD of 1.75. Find 95%confidence interval for the average household size in the city.5. A book was published entitled: “One Million Random Digits.” In it there arelisted one million (1,000,000) digits, each of course being from 0 to 9, inclusive.Suppose that there were 100,907 fives among the million digits published.How many fives were expected if the selection process were truly random? Is thisresult consistent with a random model?

Tutorial