STAT 2103 Study Guide - Final Guide: Confidence Interval, Busy Signal, European Route E6
9 May 2018
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FINAL EXAM Study Guide - Statistics 2103
Test Yourself!
Use the following to answer question 1:
In a statistics class with 136 students, the professor records how much money each student has
in their possession during the first class of the semester. The histogram below shows the data
collected.
1. The histogram
A) is skewed right. B) has an outlier. C) is asymmetric. D) All of the above. E)
None of the above
Use the following to answer question 2:
For a Physics course containing 10 students, the maximum point total for the quarter was 200.
The point totals for the 10 students are given in the stem-and-leaf display below.
(128 + 133) / 2 = M
2. The median point total for this class is
A) 130. B) 130.5. C) 133. D) 137. E) 128.
3. An office supply catalog gives a description of bookshelves that includes the following
variables. Which of these variables is categorical? (qualitative)
A) The width of a bookshelf in inches C) The color of the bookshelf
B) The width of a bookshelf in feet D) The height of a bookshelf in inches
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E) None of the above
Use the following to answer questions 4-5:
A sample was taken of the salaries of 20 employees of a large company. The following boxplot
shows the salaries (in thousands of dollars) for this year.
Box plot = 5 # Summary
4. Based on this boxplot, which of the following statements is true?
A) The maximum salary is between 60 and 70 thousand dollars.
B) The minimum salary is 40 thousand dollars.
C) The range of the middle half of the salaries is about 20 thousand dollars.
D) The median salary is about 40 thousand dollars.
E) The mean salary is 60 thousand dollars.
IQR = Q3 – Q1
IQR = 60 – 40
20
5. Based on this boxplot, which of the following statements is true?
A) All employees make over $40,000.
B) About 10 employees make over $50,000.
C) Nobody makes over $80,000.
D) both A) and B).
E) both B) and C).
6. A set of data has a mean that is much larger than the median. Which of the following
statements is most consistent with this information?
A) A histogram of the data is symmetric.
B) A histogram of the data is skewed left.
C) A histogram of the data is skewed right.
D) The data set probably has a few low outliers.
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E) None of the above.
7. A small college has 500 male and 600 female undergraduates. A simple random sample
of 50 of the male undergraduates is selected, and, separately, a simple random sample
of 60 of the female undergraduates is selected. The two samples are combined to give
an overall sample of 110 students. The overall sample is
A) a simple random sample. B) a multistage sample. C) a stratified random
sample.
D) a cluster sample E) all of the above.
Stratified = divide population into groups, then take a sample from those groups
8. Most Internet service providers (ISPs) attempt to provide a large enough service so that
customers seldom encounter a busy signal. Suppose that the customers of one ISP
encounter busy signals 8% of the time. During the week a customer of this ISP called 25
times. Use the binomial distribution to find the probability that she did not encounter
any busy signals.
A) less than 0.0001. B) about 0.1. C) 0.4602. D) 0.50. E) 0.1244
N= 25
P= .08
1 (1) (.92)25 = .1244
Use the following to answer question 9:
The temperature at any random location in a kiln used in the manufacture of bricks is normally
distributed with a mean of 1000 and a standard deviation of 50ºF.
9. If bricks are fired at a temperature above1125ºF, they will crack and must be disposed
of. If the bricks are placed randomly throughout the kiln, the proportion of bricks that
crack during the firing process is closest to
A) 49.38%. B) 2.28%. C) 47.72%. D) 0.62%. E) 0.85%.
P (x > 1125)
P ( x > 2.5) z value of 2.5 (normal table) = .4938
.5 - .4938 = .0062
Document Summary
In a statistics class with 136 students, the professor records how much money each student has in their possession during the first class of the semester. The histogram below shows the data collected: the histogram is skewed right. For a physics course containing 10 students, the maximum point total for the quarter was 200. The point totals for the 10 students are given in the stem-and-leaf display below. (128 + 133) / 2 = m: the median point total for this class is, 130. E) 128: an office supply catalog gives a description of bookshelves that includes the following variables. Which of these variables is categorical? (qualitative: the width of a bookshelf in inches, the width of a bookshelf in feet, the color of the bookshelf, the height of a bookshelf in inches. A sample was taken of the salaries of 20 employees of a large company. The following boxplot shows the salaries (in thousands of dollars) for this year.
