Q1) A random sample of ages of 51 college students has  mean of 15. Population is known to be normal with standard deviation of 2.

a) Compute standard error of mean?

b) Compute the margin of error, with 95% confidence.

Q2) Average hourly wage of workers at fast food restaurant is $6.50/hr with standard deviation of $0.45.  Suppose that distribution is normally distributed. If worker at this fast food restaurant is chosen at arbitrary, determine probability that worker earns more than $6.75?

a)  28.77%    

b)  27.64%    

c)  42.07%    

d)  5.17%

Q3) Recent study found that average life expectancy of person living in Africa is 53 years with a standard deviation of 7.5 years. If person in Africa is chosen at random, determine the probability that person will die before the age of 65?

a)  94.52%    

b)  82.89%    

c)  94.95%    

d)  88.49%