find the following percentiles for standard normal random variable z:
a- 65th percentile
b- 20th percentile
c- 90th percentile
d- 50th percentile
e- 99th percentile
2007-10-31 07:07:44 · 3 answers · asked by bob b 1 in Science & Mathematics ➔ Mathematics
the pth percentile for any distribution is the value for with p% of the data is less than or equal to the value, for example, the 97.5 percentile of the standard normal is 1.96 because P(Z < 1.96) = 0.975
I will provide you with exact values, use the cdf tables in your text book to get the approximations and see how to do this on your own.
the 65th percentile is:
0.3853205 because
P(Z < 0.3853205) = 0.65
the 20th percentile is
-0.8416212 because
P(Z < -0.8416212) = 0.20
the 90th percentile is:
1.2815516
the 50th percentile (also called the median) is
0.0000000 (or the mean for any normal random variable)
the 99th percentile is:
2.3263479
2007-11-03 17:35:41 · answer #1 · answered by Merlyn 7 · 0⤊ 0⤋
Do your own homework. It's not that hard. Think Standard Deviation.
2007-10-31 14:13:34 · answer #2 · answered by tiger b 5 · 0⤊ 2⤋
Failed math, the only statistics worth looking at are a ladies vitals. :-)
2007-10-31 14:13:59 · answer #3 · answered by rhqman 2 · 0⤊ 2⤋