2. For a sample of size 36, the standard deviation of the sample mean is 50. In order to cut this standard deviation of the sample mean to 20, we need to A) increase the sample size to 400 B) increase the sample size to 225 C) increase the sample size to 100 D) decrease the sample size to 25

3. A study at a college on the west coast reveals that, historically, 36% of the students are minority students. If a random sample of 100 students is selected, what is the probability that between 26.4% and 40.8% students in the sample will be minority students? A) 0.8150 B) 0.8385 C) 0.9735 D) There is not enough information to obtain the answer.

4. Daily observations for a period of 144 days have been conducted about the number of candy bars sold from a vending machine. Using these observations, the sample mean is calculated to be 258 and the sample standard deviation is calculated to be 60. (a) (2 points) What is the probability that the sample mean number of candy bars sold for the 144-day period is less than 273? (b) (2 points) What is the probability that the total number of candy bars sold for the 144-day period is greater than 34,992 but less than 37,872? (c) (2 points) If the profit per candy bar is 5 cents, what is the probability that the average profit per day over the 144-day period is at least $12.65?