Math Problem Statement

Consider your Statistics 213 lecture section. There are 120 students registered. Of these, 54 are Haskayne School of Business students (the remaining students belong to some other faculty). Moreover, 71 students are classified as 1st-Year students and 20 are 1st-Year students and who are not Haskayne students.

Solution

Let's analyze the problem step by step.

Given Data:

  • Total number of students: 120
  • Haskayne School of Business students (HS): 54
  • 1st-Year students (1st): 71
  • 1st-Year students who are not in the Haskayne School: 20

From the above, we can conclude the number of 1st-Year students in the Haskayne School: HS1st=7120=51\text{HS} \cap \text{1st} = 71 - 20 = 51

We can now use this information to complete the table, find the required probabilities, and answer the questions.


Part (a) - Complete the Table:

We need to fill in the joint and marginal probabilities. First, let's calculate the number of students in each category:

  1. HS and 1st (HS ∩ 1st): 51
  2. HS and not 1st (HS ∩ 1stᶜ): 54 - 51 = 3
  3. Not HS and 1st (HSᶜ ∩ 1st): 20
  4. Not HS and not 1st (HSᶜ ∩ 1stᶜ): 120 - (51 + 3 + 20) = 46

Using these, we can calculate the probabilities by dividing by the total number of students, 120:

HSHSᶜRow Probabilities
1st51120=0.4250\frac{51}{120} = 0.425020120=0.1667\frac{20}{120} = 0.16670.4250+0.1667=0.59170.4250 + 0.1667 = 0.5917
1stᶜ3120=0.0250\frac{3}{120} = 0.025046120=0.3833\frac{46}{120} = 0.38330.0250+0.3833=0.40830.0250 + 0.3833 = 0.4083
Column Probabilities0.4250+0.0250=0.45000.4250 + 0.0250 = 0.45000.1667+0.3833=0.55000.1667 + 0.3833 = 0.5500

Part (b) - Probability the student is either Haskayne or 1st-Year:

The event "Haskayne or 1st-Year" is the union of the two events: P(HS1st)=P(HS)+P(1st)P(HS1st)P(HS \cup 1st) = P(HS) + P(1st) - P(HS \cap 1st) P(HS1st)=0.4500+0.59170.4250=0.6167P(HS \cup 1st) = 0.4500 + 0.5917 - 0.4250 = 0.6167

Part (c) - Probability the student is neither Haskayne nor 1st-Year:

This event corresponds to the complement of "Haskayne or 1st-Year": P(neither HS nor 1st)=1P(HS1st)=10.6167=0.3833P(\text{neither HS nor 1st}) = 1 - P(HS \cup 1st) = 1 - 0.6167 = 0.3833

Part (d) - Proportion of 1st-Year students who are not in the Haskayne School:

This is simply the probability of being in the intersection of HSᶜ and 1st: P(HSc1st)=0.1667P(HSᶜ \cap 1st) = 0.1667

Part (e) - Are HSHS and 1st1st mutually exclusive?

Mutually exclusive events have no overlap, i.e., P(HS1st)=0P(HS \cap 1st) = 0. However, in this case: P(HS1st)=0.42500P(HS \cap 1st) = 0.4250 \neq 0 Thus, HS and 1st are not mutually exclusive. The correct option is B.

Part (f) - Are HSHS and 1st1st independent?

Two events are independent if: P(HS1st)=P(HS)×P(1st)P(HS \cap 1st) = P(HS) \times P(1st) Let's check: P(HS)×P(1st)=0.4500×0.5917=0.2663P(HS) \times P(1st) = 0.4500 \times 0.5917 = 0.2663 Since: P(HS1st)=0.42500.2663P(HS \cap 1st) = 0.4250 \neq 0.2663 Thus, HS and 1st are not independent. The correct option is D.


Would you like further details or clarifications on any of these solutions?

Here are 5 related questions to deepen your understanding:

  1. How would the table change if the total number of students increased to 150?
  2. What is the probability of randomly selecting a student who is either in 1st-Year or not in the Haskayne School?
  3. If a student is in the 1st year, what is the probability that they are also in the Haskayne School?
  4. How would independence between HSHS and 1st1st be determined using conditional probabilities?
  5. What proportion of Haskayne students are in their 1st year?

Tip: When events are independent, the occurrence of one does not influence the probability of the other.

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Math Problem Analysis

Mathematical Concepts

Probability Theory
Mutually Exclusive Events
Independent Events

Formulas

P(A ∩ B) = P(A) * P(B) for independent events
P(A ∪ B) = P(A) + P(B) - P(A ∩ B)
P(Aᶜ) = 1 - P(A)

Theorems

Law of Total Probability
Multiplication Rule for Independent Events
Addition Rule for Mutually Exclusive Events

Suitable Grade Level

University/College Level