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.
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.
Proportion 0.4317and 0.6144
d. Find the 24th percentile. Seventy six percent spend than what amount of time?
Amount of time for individuals age 75 and over in minutes =6.59
Amount of time for individuals ages 15 to 19 =19.76
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?
b. What is the probability of selecting a value at random and discovering that it has a value less than 395 pounds.