His brother would be 7 years old.
Answer:
huh?
Step-by-step explanation:
whats the questionnnnnnn
Answer: The mean of the data is 433.75, variance of the data is 99667.19 and the standard deviation of the data is 315.7011.
Explanation:
The given data is 900, 35, 500 and 300.
The number of observation is 4.
Formula of mean is,


The formula of variance is given below,



The variance of the data is 99667.19


The standard deviation of the data is 315.7011.
The other information or values of given chart is shown in the attached table.
Answer:
a) X ~ 
b) μ = 100/3
c) 
d) A battery is expected to last 100/3 months (33 months and 10 days approximately).
e) For seven batteries, i would expect them to last 700/3 months (approximately 19 years, 5 months and 10 days).
Step-by-step explanation:
a) The life of a battery is usually modeled with an exponential distribution X ~ 
b) The mean of X is μ = 1/0.03 = 100/3
c) The standard deviation is 
d) The expected value of the bateery life is equal to its mean, hence it is 100/3 months.
e) The expected value of 7 (independent) batteries is the sum of the expected values of each one, hence it is 7*100/3 = 700/3 months.
Answer: 2/3 (two thirds)
Explanation: Divide both denominator and numerator by the common factor of fourteen