I am having so much trouble with this homework. Even if you answer one part with an explanation I would be very greatful!
A criminologist developed a test to measure recidivism where low scores indicated a lower probability of repeating the undesirable behavior. (Blahblahblah) The test is normally distributed with a MEAN of 140 and a STANDARD DEVIATION of 40.
a)What is the percentile rank of a score of 172? (i got 28.81?)
b) What is the Z score for a test score of 200?
c)What percentage of scores falls between 100 and 160?
d)What proportion of respondents should score above 190?
e) Suppose and individual is in the 67th percentile in this test, what is his/her corresponding recidivism score?
Thank you so much for any help. I'd be glad to answer your open questions or choose best answer for points!
A criminologist developed a test to measure recidivism where low scores indicated a lower probability of repeating the undesirable behavior. (Blahblahblah) The test is normally distributed with a MEAN of 140 and a STANDARD DEVIATION of 40.
a)What is the percentile rank of a score of 172? (i got 28.81?)
b) What is the Z score for a test score of 200?
c)What percentage of scores falls between 100 and 160?
d)What proportion of respondents should score above 190?
e) Suppose and individual is in the 67th percentile in this test, what is his/her corresponding recidivism score?
Thank you so much for any help. I'd be glad to answer your open questions or choose best answer for points!
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Need a Normal distribution table or Graphical calculator
X~N(140 , 40^2)
a/
Pr(X<172) = 0.7881 ~ 79th percentile
b/
Z = (X - mean)/(standard deviation) = (200-140)/40 = 1.5
c/ d/ similar a/
e/ use inverse normal of 0.67 ----> X = 157.6 ~ 158
X~N(140 , 40^2)
a/
Pr(X<172) = 0.7881 ~ 79th percentile
b/
Z = (X - mean)/(standard deviation) = (200-140)/40 = 1.5
c/ d/ similar a/
e/ use inverse normal of 0.67 ----> X = 157.6 ~ 158