On a 80--question mulitpal choice test(assume 4 possible answers for each question, one of which is correct), Find the probability of getting 25 or more questions correct purely by guessing.
In a sample of 1000 people, 540 are in favor of candidate A and the rest are in favor of candidate B. Find the 95% confidence interval for the percentage in favor of canidate A:
In a sample of 600 laptop computers, 100 have defective screens. find the 95% confidence interval for the overall percent with defective screens.
For a sample of 200 sugar beet fields, the mean yield was 20 ton/acre and the standard deviation was 1.2. Find the 95% confidence interval for the mean yield for all sugar beet fields.
For a sample of 20 tires of a partiular brand, the average tread life was 65,000 miles with a standard deviation of 8000. Find the 99% confidence interval for the mean life of all tires of the brand.