Statistics and Probability Answers

First graders who misbehave in school may be more likely to be regular smokers as young adults according to a new study presented in the July 2004 issue of the American Journal of Epidemiology. After following a group of U.S. first graders for 15 years, it was found that among those kids who had tried smoking and misbehaved, 63% were daily smokers.
a) i got a just need b & c
(b) What is the probability that exactly 8 of the next 12 randomly selected young adults who misbehaved in early grades and have tried smoking are daily smokers?

(c) What is the probability that exactly 20 of the next 30 randomly selected young adults who misbehaved in early grades and have tried smoking are daily smokers?

The mean IQ score for 1500 students is 100, with a standard deviation of 15. Assuming the scores have a normal curve,

how many have an IQ between 85 and 115?

In a class of 25 students, Bill has a rank of 25th. At what percentile is he?

The mean IQ score for 1500 students is 100, with a standard deviation of 15. Assuming the scores have a normal curve,

a. how many have an IQ between 85 and 115?

b. how many have an IQ between 70 and 130?

c. how many have an IQ over 145?

Calculate the mean,median, and the mode for the following data set:
Also find the standard deviation

5,5,5,5,5,10

Christmas tree lights are used not only for Christmas trees but sometimes to decorate collegte doorm rooms. Suppose that a string has 20 light bulbs these lights are all wired in a series, so that if one light bulb fails, the whole string fails. The probability that any one light fails is 0.02. Each of the individual lights are independent of each other. What is the probability that the string will not fail?

Find the probability of rolling a 2 on a pair of dice.

suppose that heights of a 10 year old boys and girls closely follow a normal distribution with mean 51 inches and standard deviation 2 inches

a. what percentage of 10 year olds are shorter than 50 inches?
b. What percentage of 10 year olds fall between 48 and 54 inches?

A die is rolled and a coin is tossed, find the probability that the die shows an odd number and the coin shows head

1) Suppose an antibiotic has been shown to be 70% effective against a common bacteria.
a) If the antibiotic is given to five unrelated individuals with the bacteria, what is the probability that it will be effective in exactly three?
b) What is the probability that the antibiotic is effective in exactly three patients out of five (when the probability of effectiveness in a single patient is 70%).
c) What is the probability that the antibiotic will be effective in none of the five?