1.
Question
: In a survey of 500 people, 60% preferred chocolate ice cream over vanilla. How many people preferred chocolate ice cream? Answer
: 300 people preferred chocolate ice cream (500 * 0.60 = 300).
2.
Question
: The heights of students in a class follow a normal distribution with a mean of 65 inches and a standard deviation of 3 inches. What percentage of students are shorter than 70 inches? Answer
: Approximately 84.13% of students are shorter than 70 inches.
3.
Question
: A factory produces light bulbs, and the probability of a bulb being defective is 0.05. If a box contains 20 bulbs, what is the probability that at least one bulb is defective? Answer
: The probability
that at least one bulb is defective is approximately 64.15%.
4.
Question
: The average monthly salary of employees in a company is $4000 with a standard deviation of $500. What percentage of employees earn between $3500 and $4500? Answer
: Approximately 68.27% of employees earn between $3500 and $4500.
5.
Question
: A biologist is studying the growth rate of a certain species of plant. She measures the height of 50 plants and finds the mean height to be 20 inches with a standard deviation of 3 inches. Assuming a normal distribution, what is the probability that a randomly chosen plant is between 18 and 22 inches tall? Answer
: The probability that a randomly chosen plant is between 18 and 22 inches tall is approximately 68.27%.
6.
Question
: In a school, 60% of students play football, 40% play basketball, and 20% play both football and basketball. What percentage of students play at least one of the two sports? Answer
: 80% of students play at least one of the two sports.
7.
Question
: A car dealership sells three types of cars: Sedans, SUVs, and Trucks. In a month, they sold 50% Sedans, 30% SUVs, and 20% Trucks. If 10% of customers bought both Sedans and SUVs, what percentage of customers bought exactly one type of car? Answer
: 90% of customers bought exactly one type of car.
8.
Question
: The scores of a class in a math test are normally distributed
with a mean of 70 and a standard deviation of 10. What is the z-score of a student who scored 85? Answer
: The z-score of a student who scored 85 is 1.5.
