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PART 1. PART 2. Assume that a company hires employees on Mondays, Tuesdays, or W

ID: 3060201 • Letter: P

Question

PART 1.

PART 2.

Assume that a company hires employees on Mondays, Tuesdays, or Wednesdays with equal likelihood. Complete parts (a) through (c) below. a. If two different employees are randomly selected, what is the probability that they were both hired on a Wednesday? The probability is Type an integer or a simplified fraction.) b. If two different employees are randomly selected, what is the probability that they were both hired on the same day of the week? The probability is Type an integer or a simplified fraction.) c. What is the probability that 7 people in the same department were all hired on the same day of the week? Is such an event unlikely? The probability is Type an integer or a simplified fraction.)

Explanation / Answer

1.a.Probability that a randomly chosen employee was hired on a Wednesday = 1/3 (since he could have been hired on any of the 3 mentioned days with equal probability).

Hence, probability that two randomly chosen employees were hired on a Wednesday = (1/3) x (1/3) = 1/9

b.Probability that two randomly chosen employees were hired on the same day of the week = probability that they were hired on a Monday + probability that they were hired on a Tuesday + probability that they were hired on a Wednesday = (1/9) + (1/9) + (1/9) = 1/3.

c. Probability that seven randomly chosen employees were hired on a particular day of the week (let's say,Monday) = 1/(37) = 1/2187

Probability that seven randomly chosen employees were hired on the same day of the week = 3 x (1/2187) = 1/729.

Such an event is unlikely: C. Yes, because the probability that all 7 people were hired on the same day of the week is less than or equal to 0.05

2. Total number of subjects in the study = 144+160 = 304

Number of subjects who did not use Marijuana = 22 + 160 - 3 = 179

Number of subjects who tested negative = 160

Number of subjects who did not use Marijuana or tested negative = 22 + 160 = 182 (This can also be calculated as 179 + 160 - (160-3))

Probability that a randomly selected subject tested negative or didnot use marijuana = 182/304 = 0.599