MATH 215 Introduction to Statistics Assignment 1 Athabasca University

MATH 215 Introduction to Statistics Assignment 1 Athabasca University introduction to Statistics Assignment 1
Instructions
• Show all your work and justify all of your answers and conclusions, except for the TRUE/FALSE
questions.
• Keep your work to 4 decimals, unless otherwise stated.
(22 total marks)
1. Observations from the first 25 days of the year showed that the following number of pedestrians
used a particular crosswalk on each day:
19 132 25 78 62 101 84 32 99 71 43 56 64 81 59 67 43 97 105 91 31 66 76 87 125
(8 marks)
Construct a frequency distribution for this data using a lower limit for the first class of 15 and a
class width of 20. Indicate the class limits, boundaries, midpoints, frequencies and cumulative
frequencies.
Number of
pedestrians
Class
Boundaries
Class
midpoints
Frequency Relative
frequency
Cumulative
frequency
15 - 34 14.5 - 34.5 24.5 4 4/25 = 0.16 4
35 - 54 34.5 - 54.5 44.5 2 2/25 = 0.08 4+2 = 6
55 - 74 54.5 - 74.5 64.5 7 7/25 = 0.28 4+2+7 = 13
75 - 94 74.5 - 94.5 84.5 6 6/25 = 0.24 4+2+7+6 =19
95 - 114 94.5 - 114.5 104.5 4 4/25 = 0.16 4+2+7+6+4=23
115 - 134 114.5 - 134.5 124.5 2 2/25 = 0.08 4+2+7+6+4+2 = 25
Class midpoint = (upper limit + lower limit) / 2