MATH 221 Week 2 Quiz 1

MATH 221 Week 2 Quiz 1| Devry University

Week 2: Homework

Question 1

Given the following information, find the probability that a randomly selected student will be short or very short. Number of students who are very short: 45, short: 60, tall: 82, very tall: 21

Homework Help:

2DB. Probabilities from a given distribution of frequencies (Links to an external site.) (DOCX)  

·         49.5%  

·         21.0%  

·         28.8%    

·         50.5%

 Question 2

Given the following information, find the probability that a randomly selected dog will be a golden retriever or a poodle. Number of dogs who are poodles: 31, golden retrievers: 58, beagles: 20, pugs: 38

2DB. Probabilities from a given distribution of frequencies (Links to an external site.) (DOCX)  

·         46.9%  

·         60.5%  

·         39.5%  

·         58.0%

 Question 3

Given that there is a 28% chance it will rain on any day, what is the probability that it will rain on the first day and be clear (not rain) on the next two days?

2VA: Probabilities given probability of success and 2 or more events (Links to an external site.) (0:51)

2DC. Probabilities given probability of success and 2 or more events (Links to an external site.) DOCX)  

·         34.7%  

·         5.6%    

·         14.5%   

·         20.2%

Question 4

Consider the following table. What is the probability of blue?

                Red        Blue       Green   Total

Yes         33           44           14           91

No          18           5              28           51

Total      51           49           42           142

2VB: Conditional probabilities from a table (Links to an external site.) (1:45)  

·         91/142  

·         49/142  

·         51/142  

·         44/49

Question 5

Consider the following table. What is the probability of red, given yes?

                Red        Blue       Total

Yes         15           21           36

No          38           13           51

Total      53           34           87

2VB: Conditional probabilities from a table (Links to an external site.) (1:45)  

·         15/21    

·         15/36  

·         15/53  

·         53/87

Question 6

In a sample of 350 customers, 125 say that service is poor. You select two customers without replacement to get more information on their satisfaction. What is the probability that both say service is poor?

2VE: Probabilities of drawing several from many without replacement (Links to an external site.) (1:35)

2DE. Probabilities of drawing several from many without replacement (Links to an external site.) (DOCX)  

·         14.29%    

·         12.69%  

·         41.67%  

·         12.76%

 Question 7

Some days, the CEO holds meetings and some days the CEO is wearing blue shoes. How would you most likely classify these events?

2DF. Independent versus dependent events; mutually exclusive and non-mutually exclusive events, complements (Links to an external site.) (DOCX)  

·         Independent  

·         Dependent

 Question 8

Of the shirts produced by a company, 5% have loose threads, 9% have crooked stitching, and 3.5% have loose threads and crooked stitching. Find the probability that a randomly selected shirt has loose threads or has crooked stitching.

2VF (1): Probabilities using the addition rule with values (Links to an external site.) (0:54)

2DG. Probabilities using addition rule (Links to an external site.) (DOCX)  

·         10.5%  

·         17.5%  

·         14.0%  

·         0.5%

 Question 9

Randomly select a customer that is happy with the company. Randomly select a customer who is elderly. Are these events mutually exclusive?

Homework Help:

2DF. Independent versus dependent events; mutually exclusive and non-mutually exclusive events, complements (Links to an external site.) (DOCX)  

·         Non-mutually exclusive events 

·         Mutually exclusive events

Question 10

In a sample of 780 adults, 209 said that they liked sugar cereals. Three adults are selected at random without replacement. Find the probability that all three like sugar cereals.

Homework Help:

2VG: Probabilities of drawing several from many without replacement, all or none outcomes (Links to an external site.) (2:16)

2DH. Probabilities of drawing several from many without replacement, all or none outcomes (Links to an external site.) (DOCX)  

·         1.92%  

·         2.98%    

·         1.90%  

·         8.93%

 Question 11

A sock drawer has 17 folded pairs of socks, with 7 pairs of white, 6 pairs of black and 4 pairs of blue.  What is the probability, without looking in the drawer, that you will first select and remove a black pair, then select either a blue or a white pair?

Homework Help:

2VH (1): Probability with multiplication rule: with numbers (Links to an external site.) (1:30)

2DI. Probability with the Multiplication Rule – with Numbers (Links to an external site.) (DOCX)  

·         24.26%  

·         22.84%   

·         64.71%  

·         35.25%

Question 12

An investment advisor believes that there is a 60% chance of making money by investing in a specific stock. If the stock makes money, then there is a 50% chance that among those making money, they would also get a dividend. Find the probability that the investor makes money and receive a dividend.

2VH (2): Probability with multiplication rule: with percentages (Links to an external site.) (0:58)

2DJ. Probability with the Multiplication Rule - with Percentages (Links to an external site.) (DOCX)  

·         10%  

·         60%  

·         30%  

·         50%

 Question 13

An investment advisor believes that there is a 28% chance of making money by investing in a specific stock. If the stock makes money, then there is a 43% chance that among those making money, they would also get a dividend. Find the probability that the investor makes money but does not receive a dividend.

2VH (2): Probability with multiplication rule: with percentages (Links to an external site.) (0:58)

2DJ. Probability with the Multiplication Rule - with Percentages (Links to an external site.) (DOCX)  

·         18%  

·         28%    

·         16%  

·         15%

 Question 14

A smartphone company found in a survey that 20% of people did not own a smartphone, 28% owned a smartphone only, 14% owned a smartphone and only a tablet, 13% owned a smartphone and only a computer, and 25% owned all three. If a person were selected at random, what is the probability that the person would own a smartphone only or a smartphone and computer?

2VF (2): Probabilities using the addition rule with percentages (Links to an external site.) (1:01)

2DG. Probabilities using addition rule (Links to an external site.) (DOCX)  

·         42%  

·         80%  

·         41%  

·         28%

 Question 15

Match the terms and their definitions

2DA. Definition of probabilities and classical, empirical, subjective probabilities (Links to an external site.) (DOCX)

2DF. Independent versus dependent events; mutually exclusive and non-mutually exclusive events, complements (Links to an external site.) (DOCX)

·         0 and 1             

·         1 - P(E)               

·         The occurrence of one event does not affect the occurrence of the other             

·         Cannot occur at the same time             

·         Probability of an event given that another event has occurred