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Unformatted text preview: 1) 3) 4) i é go EXAMl sample A large community college has noticed that an increasing number of full~timc students are working
while attending the school. The administration randomly selects 128 fulltime students and asks
this question: How many hours per week do you work? a)What is the population of interest and what is the sample?
b) What is the variable of interest? What type of variable is it? Attendance and grades A marketing research gIUup working for a large franchise restaurant wants to see if the residents of
San Marcus, Texas are interested in having their restaurant built in the city. The marketing
research ﬁrm found that 700 out of the 1,000 randomly selected residents are in favor of having the
testament in their city. The researchers note that 70% of the selected San Marcos residents are in
favor of having the restaurant. 13 this descriptive or inferential statistics? Explain. A local community conducted a survey on the amount of money its students spend per month on
gas expenses. The Histogram below shows you a distribution of the data collected. Histogram 12 _.
0 Frequency
(2 N J: O) on 325.5: zitWU 42'5"}: +15  515 ' 575” 62“: 67!“ Monthly Gas Expenses in Dollars a) Describe the shape of the Histogram.
_ I b) How many students had monthly Spending that exceeded 1 19.5?   \ c) What percentage of monthly spending is less than 104.5? ‘ d) Given the shape of the histogram, What measure of center (mean or median) would you expect
to be the largest? Why? e) Find the class midpoint for each class. t) Find the samplgiaﬂanm.... 5) With the following sample data: 3.8 106 12.4 3.8 a) Compute the sample mean Be sure to show all of your work and use the appropriate symbol.
} i ‘ ' b} Compute the sample standard deviation. Be sure to Show all of your work, including the
necessary table, and use the appropriate symbol. 6) A supermarket manager selected 16 random shoppers at her store from 4—6pm and observed the
following spending from her patrons (in dollars) : 120,111,141,153,113, 1.14; 126, L21} 135,122,123",'136,139,14.3*,139,183
a) Create a stem plot of the data b)As a way of measuring the spread, ﬁnd the ﬁrst and third quartile values of the sample data.
c) Draw boxplot. . U '7. j The mean for 199 randomly sampled British women's heights is 1602
millimeters, and the standard deviation is 62.4 millimeters. Use the Empirical Rule to
answer the questions on parts a—d. 3) Approximately what percent of women’s heights are less than 1477.2 millimeters? Answer b) Approximately what percent of women‘s heights are less than 1789.2 millimeters? Answer c) Approximately 95% of the women‘s heights are between what two values? Answer d) Approximately what percent of women’s heights are between 1414.8 millimeters and
1664.4millimeters? Answer 3 '1 L" i .' Ten people in a room have an average height 5 feet 7 inches. An 11“ person
/ enters the room. How tall would he have to be to raise the average height by  inch? 0'“) Find the area between 0‘] and 0.25 under the normal curve. _ \ [7) Find the area between —1.2 and 2.15 under the normal curve. C) Find the area to the right of 3 under the nonnal curve. d) Find the area to the right of —1 .6 under the normal curve. ' r r)
'9) Find a positive number 2 so that 46% ofthe area under the normal curve lies bexween 0 and z. .19. C» 5 Suppose the boxes with the fewest 2
are shipped to the stores. What is the minimal
box? [Note: This problem could be rephrased % of From Loops are reviewed before Ihey
acceptable number of Free: Loops per
“Find the 2“ percentile.”] "U‘l' ...
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 Spring '08
 Patton
 Normal Distribution, Standard Deviation, San Marcos

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