The time until recharge for a battery in a laptop computer under common conditions is normally distributed with mean of 270 minutes and a standard deviation of 50 minutes.
a) What is the probability that a battery lasts more than four hours? Entry field with incorrect answer (Round the answer to 3 decimal places.)
b) What are the quartiles (the 25% and 75% values) of battery life?
25% value (Round the answer to the nearest integer.)
75% value (Round the answer to the nearest integer.)
c) What value of life in minutes is exceeded with 95% probability? Entry field with incorrect answer (Round the answer to the nearest integer.)
1 answer
http://davidmlane.com/hyperstat/z_table.html