probability that 110 or more people in this sample have had chickenpox in their childhood.

A dean in the business school claims that GMAT scores of applicants to the school's MBA program have increased during the past 5 years. Five years ago, the mean and standard deviation of GMAT scores of MBA applicants were 550 and 60, respectively. 30 applications for this year's program were randomly selected and the GMAT scores recorded. If we assume that the distribution of GMAT scores of this year's applicants is the same as that of 5 years ago, find the probability of erroneously concluding that there is not enough evidence to supports the claim when, in fact, the true mean GMAT score is 590. Assume αα is 0.02.

The length of human pregnancies from conception to birth is approximately Normal with a mean  length of 266 days and a standard deviation of 16 days.  What is the probability that the average pregnancy length for 7 randomly chosen women exceeds 270 days?

The probability of relapse into alcoholism can be modeled with a discrete random variable with mean ? = 4 years. Find the probability that a person will not reoffend in the first 2 years.

What is the probability that a randomly chosen individual would be less than 64.5 years of age? Show how you standardized the problem.

State the null and alternative hypothesis if I claim that the mean lifespan of African elephants is 59 or less.

Please Help ASAP!!!