The Bureau of Labor Statistics’ American Time Use Survey showed that the

1. The Bureau of Labor Statistics’ American Time Use Survey showed that the amount of time spent using a computer for leisure varied greatly by age. Individuals age 75 and over averaged .40 hour (24 minutes) per day using a computer for leisure. Individuals ages 15 to 19 spend 1.2 hour per day using a computer for leisure. If these times follow an exponential distribution, find the proportion of each group that spends:
   a. Less than 20 minutes a day using a computer for leisure. (Round answer to 4 decimal places)
   Proportion 0.5654and 0.2425
   b. More than 2 hours. (Round answer to 4 decimal places)
   Proportion 0.0067 and 0.1889
   c. Between 20 and 140 minutes using the computer for leisure. (Round answer to 4 decimal places)
   Proportion 0.4317and 0.6144
   d. Find the 24th percentile. Seventy six percent spend than what amount of time? (Round to 2 decimals)
   Amount of time for individuals age 75 and over in minutes =6.59
   Amount of time for individuals ages 15 to 19 =19.76
   
2. The mean of a normal distribution probability is 400 pounds. The standard deviation is 10. 
   a. What is the area between 415 pounds and the mean of 400 pounds? (Round to 4 decimals)

b. What is the probability of selecting a value at random and discovering that it has a value less than 395 pounds. (Round to 4 decimals)