5) Defective Masks In a batch of 100 Rubber masks, there are, on average, 10 def

Question

5)        Defective Masks In a batch of 100 Rubber masks, there are, on average, 10 defective ones. If a random sample of 10 is selected, find the probability of 4 defective ones.

6)        Mispronounced incantations: For some reason the characters in scary movies can’t pronounce there eldritch words correctly. It has been estimated that 3 out of every 5 words is mispronounced! Given an incantation of 15 words find the following:

a)      exactly 5 are said correctly

b)      at most 7 words are said correctly

c)       less than 4 words are said correctly

d)      Between 3 and 7 words out of nine are said correctly

7)        Spook-Treat Bags In a survey of choosie Dads, 60% said they use pillowcases for their trick-o-treating needs, 30% said they use hard plastic, and 10% said ‘bags…???’. You take a sample of the first 7 trick-o-treaters that come to your door, 4 pillowcases, 1 hard plastic and 2 with no bags. What is the likelihood of this happening?

Explanation / Answer

5)

p = 10/100 = 0.1

P(x=4) = 10C4 * 0.1^4 * 0.9^6 = 0.0112

6)

a)

P(X=5) = 15C5 * (3/5)^5 * (2/5)^10 = 0.0245

b)

P(X<=7) = binomialcdf(15,7,0.6) = 0.2131

c)

P(X<=4) = binomialcdf(15,4,0.6) = 0.2173

Related Questions

Navigate

• Browse (All)
• Browse 5
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.