In: Statistics and Probability
In 2002 the mean age of an inmate on death row was 40.7 years with a standard deviation of 9.6 years. A sample of 32 current death row inmates shows a mean age of 38.9 years. Does this indicate that the mean age of death row inmates is less than in 2002?
Solution :
Given that,
mean =
= 40.7
standard deviation =
= 9.6
n = 32
= 40.7
=
/
n = 9.6 /
32=1.697
P(
< 38.9) = P[(
-
) /
< (38.9-40.7) /1.697 ]
= P(z <-1.06 )
Using z table
= 0.1446
probability= 0.1446
yes this indicate that the mean age of death row inmates is less than in 2002