Statistics

The probability of a defect in a collection of bolts is 5%. If a man picks 2 bolts, what is the probability that he does not pick 2 defective bolts?

3 randomly chosen senior high school students were administered a drug test. Each student was evaluated as positive (P) or negative (N). Assume the possible combinations are PPP, PPN, PNP, NPP, PNN, NPN, NNP, NNN, each equally likely. What is the probability that at least 1 student gets a negative result?

The probability that A can solve a given problem is 4/5, that B can solve it is 2/3, and that C can solve it is 3/7. If all three try, compute the probability that the problem will be solved.

Find the upper quartile in the set (0, 1, 3, 4).

In a debate on two issues among 32 people, 16 agreed with the first issue, 10 agreed with the second issue, and of these 7 agreed with both. What is the probability of selecting a person at random who did not agree with either issue?

If 15% of the bolts produced by a machine are defective, determine the probability that out of 5 bolts chosen at random, at most 2 bolts will be defective.

A fair coin is tossed three times. Find the probability that there will appear three heads.

A coin is tossed n times. If it is expected that 7 heads will occur, how many times is the coin tossed?

From past experience, it is known that 90 percent of one-year-old children can distinguish their mother’s voice from a similar sounding female. A random sample of 20 one-year-olds is given this voice recognition test. Find the standard deviation of the number of children who recognize their mother’s voice.

The average of six scores is 83. If the highest score is removed, the average of the remaining scores is 81.2. Find the highest score.

A school has 5 divisions in class IX having 60, 50, 55, 62 and 58 students. Mean marks obtained in a History test were 56, 64, 72, 63 and 50 by each division respectively. What is the overall average of the marks per student?

The probability that a randomly chosen sales prospect will make a purchase is 0.18. If a salesman calls on 5 prospects, what is the probability that the salesman will make exactly 3 sales?