Homework Assignment 1
Exercise 1
For the following, indicate whether they are a population, a sample, variables
a) current weights of all living former presidents of the United States
b) attitudes of 50 Vietnameses toward immigrant as measured on a ve-point
scale from 1 (=unfavorable) to 5 (favorable)
c) all remaing 132 butteries in a species that going extinct.
d) all men who have stood on the surface of the moon
e) blood-sugar levels in all living women with diabtes
f) the diameters in meters of all circles
g) white rats being used in a psychology experiment.
Exercise 2
The following data show the top 85 nishing times (in minutes) for males runner
in a Boston marathon.
129, 130, 130, 133, 134, 135, 136, 136, 138, 138, 138, 141, 141, 141,
142, 142, 142, 142, 143, 143, 143, 143, 143, 144, 144, 145, 145, 145,
145, 145, 146, 146, 146, 146, 147, 147, 147, 148, 148, 148, 148, 148,
148, 149, 149, 149, 149, 149, 150, 150, 150, 150, 151, 151, 151, 151,
152, 152, 152, 152, 152, 152, 152, 152, 152, 153, 153, 153, 153, 153,
153, 153, 153, 153, 153, 153, 154, 154, 154, 154, 154, 154, 154, 154,
154
Put the 85 nishing times into a K class where K is dened as
10
log10 (n)
K∼
=1+
3
a) Determine the class limits, class boundaries, class marks.
b) Determine the grouped frequency distribution, grouped relative frequency distribution, less than cumulative frequency, and less than cumulative relative frequency.
c) Make a histogram of relative frequency for this kind of grouped data.
Exercise 3
An economist studying trends in a gasoline prices within a city takes a simple
random sample of 40 of the city's gas stations, determining for each station the
price per gallon (in dollars) of unleaded regular gasoline. Here are the results,
presented in an ascending array: 1.05, 1.07, 1.07,1.08,1.10, 1.10,1.10,1.10,1.10,
1.10,1.10,1.10,1.10, 1.10,1.10,1.10, 1.11,1.11,1.11,1.11,1.11,1.11,1.11,1.11,1.11,1.11,
1.12,1.12,1.12,1.12,1.12,1.13,1.131.13,1.13,1.14,1.14,1.14,1.15,1.15
a) Put this array into a summary table with columns for price, frequency, relative frequency, less than cumulative frequency, and less than cumulative relative
frequency.
b) Make a histogram of relative frequency distribution for these data.
Exercise 4
You are an engineer studying the performance of a new air conditioning system
in a 60 story building. To evaluate the temperature in the building, set by the
system at 72o F you take a simple random sample of 20 rooms and measure their
temperatures to the nearest o F . Here are the results represented in an ascending
array: 69, 69, 70, 70, 70, 70, 72, 72, 72, 72, 72, 72, 72, 72, 72, 72, 73, 73, 74, 74.
a) Put this array into a summary table with columns for temperature, frequency,
relative frequency, less than cumulative frequency, and less than cumulative relative frequency.
b) Make a histogram of relative frequency distribution for these data.
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