**Unformatted text preview: **Chapter 2 Worksheet Name 6f 3
Normal Distributions l. The height of young American women has an approximately normal distribution
with mean u = 65.5 inches and standard deviation 5 = 2.5 inches. Find the
relative frequencies of each of the following (draw and shade the appropriate regions of a normal curve):
a. a woman is less than 67 inches tall / 2" POM Q7) 3
72.4% / W, 50(24 .c.) z .7257 b. a woman is between 64 and 67 inches tall in “new. at <67)
9/3522 % :p(,,(,4?4.a)
2. The Graduate Record Exam (GRE) is widely used to help predict the c ”32:39 926% ‘5)
performance of appl'cants to gaduate school. The range of possible scor 's o ,f
the each portion of the test is 200 to 800. A university ﬁnds that the scores of its applicants on the quantitative portion of the GRE are approximately normal with mean u = 544 and standard deviation 0' = 103. Find:
a. the relative ﬁequency of a score greater than 700 éfg 0/0 p(><77oo):l9(27l.s:): l-F’C-‘td-SI): .0425; .
b. the relative frequency of a score between 500 and 800
‘ Gé'éb/b P W4 1‘ 52:0) 2 l- (4149») = l-PCEC -.‘i3)-_—_ I'IWE '1' c. how high you must score to be in the top 10% of the p ulation.
~ 40*“ para/M! :7 2 = 1-2: 122;. s m @172?
3. The Chapin Social Insight Test evaluates‘how accurate y some praises other people. Scores are approximately normally distributed with mean n == 25 - and standard deviation o = S. The range of possible scores is 0 to 41. 0
a. What percent of the population has scores below 20?
pacer): FLU-~13 = Jew [5,67%
b. Above 38‘?
00:7 55’): 1— 13(24 2.5.) : ,oovt 7 c. How high must you score in order to be in uarter of the population? 2.7: = .67 , .07 z x — 29 I
...__..3_. 4. The median of any normal distribution is the same as its mean. We can use the
standard normal table to ﬁnd the quartiles and related descriptive measures for normal distributions.
a. What are the ﬁrst and third quartiles of the standard normal distribution? "' . [o7 mall . Ca 7
b. What is the value of the IQR for the standard normal distribution? 1-3’7’ c. What percent of the observations in the standard normal distribution are suspected outliers according to the 1.5 x IQR criterion?
LS" . L 314 : 2.01 “$41.01!, about ’2.st an! lav/.99 —2.6? .0037 a. each emf, 50 0,7177% W— ...

View
Full Document