School

University of California, Berkeley **We aren't endorsed by this school

Course

STAT 155

Subject

Statistics

Date

Aug 25, 2023

Pages

2

Uploaded by ChancellorTank11853 on coursehero.com

STAT 155 -
Summer Session A 2022
Exam 1 (CH 1-3)
SSA22 STAT 155 AFlores
Exam Details
Total Points:
100 =
3
(practice PDF upload)
+ 97
(exam questions)
Course Percentage:
30%
Exam Policies
•
Students are allowed to use a calculator and course materials (lecture notes, course textbook,
homework, quizzes, discussion notes) during the exam. Students should not use resources
outside of the course materials and should not discuss or work on the exam with anybody.
Exams are not open internet/resources and collaboration is strictly prohibited.
•
Students may complete the exam electronically using a tablet or by writing on blank paper or
a printed exam copy.
•
Students will be required to upload a PDF of their solutions to Canvas.
•
Students should remain logged in to the Zoom meeting with their camera on and mic muted
for the entirety of the exam. Note: The exam Zoom meeting will be recorded.
•
This exam is protected by copyright and cannot be posted to any websites or shared in
any manner at any time before, during, or after the exam.
Exam Instructions
8 - 9:30am
Read and complete each exam question. 1-3 questions will be released every half
hour (i.e., 8am, 8:30am, 9am). You will have 30 minutes to complete the solution
and upload a PDF file showing your work / solution. Once the 30 minutes (from
the question release time) has passed, no other submissions will be allowed (i.e.,
you will not be able to go back to that question).
Solutions should include all appropriate steps, statistical notation, mathematical work, and
numerical results. Be sure to number your problems and show your work in an organized manner.
Numerical calculations should be rounded to 4 decimal places.
Good Luck!
Exam Honor Pledge
HONOR PLEDGE:
I agree that I will complete this exam with integrity and honesty. The work
I submit for the exam will solely be my own. I will not use any non-approved materials, electronic
devices, or other aids to assist me on the exam. I will not post this exam to any websites or share
it in any manner at any time before, during, or after the exam.
By uploading your PDF solutions to Canvas, you are confirming that you agree to and have
completed the exam in accordance with the above Honor Pledge.

STAT 155 -
Summer Session A 2022
Exam 1 (CH 1-3)
SSA22 STAT 155 AFlores
Question 1
:
A mechanical engineer analyzing the runtime of oil pumps (measured in years)
tracks the time until a pump fails and is pulled out of ground for repair or replacement. A random
sample of runtimes are provided below:
1.2
1.6
4.9
5.7
5.9
6.3
6.5
6.8
6.8
6.8
7.1
10.3
11.0
a)
Identify the experimental unit. [2 pts]
_________________________________________
b)
Identify the variable of interest. [2 pts]
_________________________________________
c)
Identify the type of variable (circle one). [1 pt]
qualitative
discrete
continuous
d)
What is the mean runtime for the oil pumps in this sample? [4 pts]
e)
What is the value of the upper quartile for this sample? Be sure to support your work by
including the calculation for the position of the upper quartile. [8 pts]
f)
Calculate the trimmed mean by eliminating the two smallest and two largest runtimes (which
appear to be somewhat different than the remaining observations). Identify the corresponding
trimming percentage. [8 pts]
g)
Suppose the observation equal to 6.5 years is changed to 6.8 years. Which of the following
descriptive statistics would change in value? Select all that apply or select NONE if none of
the values would be affected. [6 pts]
Mean
Variance
Lower Quartile
Range
Mode
Median
Standard Deviation
Upper Quartile
IQR
NONE

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