Practice Test 3
Name _
Online Math 115
MCC Student ID # (or Surf ID #) _ _ _ _ _ _ _ _
Date: _ /_ /_
Please use this Practice Test to help you study for the actual Test 3. Test 3 will be shorter though.
Study and review for Test 3. Then work the problems
Chapter 12 Solutions
12.]. There are 22 observations, and the median lies halfway between the middle pair (the llh
and l21h largest). The middle two values are 35 and 4l , so the median is M : (35 + 4l)/2 = 76/2
: 38. There are ll observations to the left
Chapter 14 Solutions
14.1. The researchers are seeking to predict lQ from brain size. Thus, there is an explanatory
variable (brain size). The response variable is lQ. The following is a scatterplot of the data:
1405
62
1301
120-
3 110-
%$
100-
Chapter 19 Solutions
19.1. In a standard deck of cards, 13 of the cards are spades, 13 are hearts, 13 are diamonds, and
13 are clubs. We need two digits to simulate one draw:
00, 01, ., 12 1 spades
13, 14, 25 = hearts
26, 27, 38 2 diamonds
39, 40, ., 51 1
Part II Review Solutions
11.1. The distribution could be Viewed as roughly symmetric, with Mississippi being an outlier.
0 77
0 8899
1 00011
1 222233
1 44455
1 667
1
2 0
-equency
8 10 12 14 16- , 18 20
Percentage of state residents living in pov
Chapter 15 Solutions
15.1. The predicted humerus length for a fossil with a femur 70 cm long is
humerus length : ~3 .66 + (l.197)(70)
280.13cm
15.2. The proportion of the variation in hot dog prices that is explained by the least-squares
regression of hot
Chapter 3 Solutions
3.1. The margin of error for 95% condence will be about
1 1 : 0.030 (that is, 3.0%).
4/1077 : 32.82
3.2. The margin of error for 95% condence will be about
1 a _l_ .4. 0.016 (that is, 1.6%)
./4000 2 63.24
It is smaller than for a sampl
Part IV Review Solutions
IV.1. We have [7: 133
1025
[iii lp(1p)=0.1298i2 /19_2_21%:95-_8]922 20.1298i00210.
H
We are 95% condent that the proportion of all adults who were victims otcomputer or Internet
crime in the 12 months prior to October 2010 is betw
Chapter 6 Solutions
6.]. There are two explanatory variables. These are baking temperature (300, 320, and 340W)
and baking time (1 hour and 1 hour, 15 minutes). The responses are the scores of the panel of
tasters for texture and taste. For each cake, the
Chapter 8 Solutions
8.]. The number of drivers is usually much larger between 5 and 6 PM. (rush hour) than between
I and 2 RM. Thus, we would expect the number of accidents to be greater between 5 and 6 PM.
than between 1 and 2 PM. It is therefore not sur
Chapter 10 Solutions
10.1. The state variable is a categorical variable; for categorical variables, we should use either
a bar graph or a pie chart. However, because the percentages do not add up to 100%, a bar graph
is most appropriate.
10.2. The price o
Chapter 21 Solutions
21.]. The 95% condence interval for the proportion of all adult Americans who believe
gambling is morally wrong is
[3+2 fanf9) :0 31+2 1031(069)
n ' 1018
= 0.31 i 2(0.014)
: 0.31 i 0.028
= 0.282 to 0.338.
Interpret this result as fol
Chapter 24 Solutions
24.1. The expected count of students with average grades of As and Bs who have played games
is
row 1 total x row 2 total
table total
.- (l 379)(941)
1808
expected count =
= 717.7.
24.2. To nd the chisquare statistic, we add six terms
Chapter 1 1 Solutions
11.1. Step 1: Divide the range of the data into classes of equal Width. The data in the table
range from 20.8 to 31.1, so we choose as our classes
20.0 S percentage under age 18 < 21.0
21 .0 S percentage under age 18 < 22.0
31.0 S pe
Chapter 4 Solutions
4.]. This question is clearly slanted toward a positive Yes response because the question asks
the respondent to consider escalating environmental degradation and incipient resource
depletion.
4.2. Label faculty 0, 1, 2, 3, 4. Label st
Chapter 22 Solutions
22.1. The hypotheses. The null hypothesis says that the coin is balanced (p = 0.5). We do not
suspect a bias in a specic direction before we see the data, so the alternative hypothesis is just
the coin is not balanced. The two hypothe
Chapter 13 Solutions
13.1. The middle 95% of any Normal distribution lies within two standard deviations of the
mean. Two standard deviations is 5 inches here. so the middle 95% of young mens heights is
between 65 inches (thats 70 5) and 75 inches (that's
Chapter 20 Solutions
20.1. The expected value is (0)(0.55) + (1)(0.19) + (2)(0. 1 7)+ (3)(0.07) + (4x002) = 0.82.
20.2. Answers will depend on the starting point in Table A and on the assignment oftwodigit
pairs. Use 00 to 44 to represent a made shot and
Part 111 Review Solutions
111.1. (a) Results will vary among phone books. (b) If all are equally likely, this would be 0.3, or
30%. In some phone books, they may appear to be reasonably close to equally likely.
Note: For a situation in which they might no
Chapter 9 Solutions
9.1. This is not plausible. From the information given, we can determine how many melons are
produced per square foot:
75 0, 000 melons 1 acre
>< W-uf :17 melons per sq. ft.
acre 43,560 sq. it.
melons per sq. foot 2
So, as stated, the
Chapter 5 Solutions
5.1.
. Treatment 1
Group I -~-> supervised
2000 men .
exercrse
\ Compare
Random incidence of
assignment / heart attacks
Group 2 W" Treatment 2
2000 men usual habits
5.2. (a) Explanatory variable: whether a person lives within 100 meter
Chapter 18 Solutions
18.1. Let a pair of numbers represent the number of spots of the upfaces of the first and second
die, respectively. The probability of rolling a 7 is
P(roll a 7) = P(l. 6) + P(2, 5) + P(3,4) + P(4,3) + P(S, 2) + P(6. 1)
l l 1 l l+l:6:
Chapter 17 Solutions
17.1. All of the outcomes are equally probable if the coin is fair because heads and tails are
equally likely. Thus all sequences of 10 particular outcomes are equally likely.
17.2. A correct statement might be, If you tossed a coin a
Part 1 Review Solutions
1.1.~I.2. Student answers will vary.
1.3. It is a convenience sample; she is only getting opinions from students who are at the student
center at a certain time of day. This might underrepresent some group(s): commuters, graduate
s
Chapter 2 Solutions
For these exercises, remind students that the population is the group about which information is
desired. The population is not necessarily the group represented by the sample.
2.1. This is not a simple random sample. Not every possibl
Chapter 23 Solutions
23.1. We would like to know both the sample size and the actual mean weight loss before
deciding whether we nd the results convincing. Better yet, we would like to know exactly how
the study was conducted and to have the actual data.
Chapter 7 Solutions
Many of the questions in this chapter are matters of opinion and may be better used for class
discussion rather than as assigned homework. A few comments are included here.
7.1. This is a complicated Situation. This patients underlying
Chapter 1 Solutions
1.1. Population: The population is not explicitly defined. From the context of the problem, we
assume it to be all adult Americans. However, with a phone survey, the population might be
more appropriately dened as adult Americans with
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