In: Statistics and Probability
Question 1
Fifteen golfers are randomly selected. The random variable
represents the number of golfers who only play on the weekends. For
this to be a binomial experiment, what assumption needs to be
made?
The probability of golfing on the weekend is the same
for all golfers
The probability of golfing during the week is the same
for all golfers
All fifteen golfers play during the week
The probability of being selected is the same for all
fifteen golfers
Question 2
A survey found that 39% of all gamers play video games on their
smartphones. Ten frequent gamers are randomly selected. The random
variable represents the number of frequent games who play video
games on their smartphones. What is the value of n?
0.39
x, the counter
0.10
10
Question 3
Thirty-five percent of US adults have little confidence in their
cars. You randomly select ten US adults. Find the probability that
the number of US adults who have little confidence in their cars is
(1) exactly six and then find the probability that it is (2) more
than 7.
(1) 0.069 (2) 0.005
(1) 0.069 (2) 0.974
(1) 0.021 (2) 0.005
(1) 0.021 (2) 0.026
Question 4
Say a business wants to know if each salesperson is equally
likely to make a sale. The company chooses 5 salespeople and
gathers information on their sales experiences. What assumption
must be made for this study’s probability results to be used in
future binomial experiments?
That for every 5 salespeople, the probability of
making a sale is the same
That the probability of each salesperson being one of
the selected 5 is the same
That 5% is the correct probability to use in future
studies
That the selected 5 have similar characteristics and
sales areas as the other salespeople
Question 5
A soup company puts 12 ounces of soup in each can. The company
has determined that 97% of cans have the correct amount. Which of
the following describes a binomial experiment that would determine
the probability that a case of 36 cans has all cans that are
properly filled?
n=36, p=0.97, x=36
n=36, p=0.97, x=1
n=12, p=0.36, x=97
n=12, p=0.97, x=0
Question 6
A supplier must create metal rods that are 2.3 inches width to
fit into the next step of production. Can a binomial experiment be
used to determine the probability that the rods are the correct
width or an incorrect width?
No, as the probability of being about right could be
different for each rod selected
Yes, all production line quality questions are
answered with binomial experiments
No, as there are three possible outcomes, rather than
two possible outcomes
Yes, as each rod measured would have two outcomes:
correct or incorrect
Question 7
In a box of 12 pens, there is one that does not work. Employees
take pens as needed. The pens are returned once employees are done
with them. You are the 5th employee to take a pen. Is this a
binomial experiment?
No, binomial does not include systematic selection
such as “fifth”
No, the probability of getting the broken pen changes
as there is no replacement
Yes, you are finding the probability of exactly 5 not
being broken
Yes, with replacement, the probability of getting the
one that does not work is the same
Question 8
In a box of 12 pens, there is one that does not work. Employees
take pens as needed. The pens are returned once employees are done
with them. You are the 5th employee to take a pen. Is this a
binomial experiment?
No, binomial does not include systematic selection
such as “fifth”
No, the probability of getting the broken pen changes
as there is no replacement
Yes, you are finding the probability of exactly 5 not
being broken
Yes, with replacement, the probability of getting the
one that does not work is the same
Question 9
Sixty-one percent of employees make judgments about their
co-workers based on the cleanliness of their desk. You randomly
select 8 employees and ask them if they judge co-workers based on
this criterion. The random variable is the number of employees who
judge their co-workers by cleanliness. Which outcomes of this
binomial distribution would be considered unusual?
0, 1, 7, 8
0, 1, 2, 8
1, 2, 8
1, 2, 7, 8
Question 10
Sixty-eight percent of products come off the line within product
specifications. Your quality control department selects 15 products
randomly from the line each hour. Looking at the binomial
distribution, if fewer than how many are within specifications
would require that the production line be shut down (unusual) and
repaired?
Fewer than 8
Fewer than 9
Fewer than 11
Fewer than 10
Question 11
The probability of a potential employee passing a drug test is
86%. If you selected 12 potential employees and gave them a drug
test, how many would you expect to pass the test?
8 employees
9 employees
10 employees
11 employees
Question 12
Off the production line, there is a 3.7% chance that a candle is
defective. If the company selected 45 candles off the line, what is
the probability that fewer than 3 would be defective?
0.975
0.916
0.768
0.037
Question 1
The 4 Characteristics of a Binomial Experiment
Here we see that The random variable represents the number of golfers who only play on the weekends, so success is if he plays on the weekends
Hence assumption needs to be made is "The probability of golfing on the weekend is the same for all golfers"
Question 2. Here it is given that Ten frequent gamers are randomly selected. Hence sample size is n=10
Question 3. As all the assumptions of binomial are satisfied we will use binomial formula to find the required probability, here p=0.35 and n=10
Hence answer is (1) 0.069 (2) 0.005
Question 4.
The 4 Characteristics of a Binomial Experiment
So answer is That for every 5 salespeople, the probability of making a sale is the same as here we want to know if each salesperson is equally likely to make a sale