Three defective electric toothbrushes were accidentally shipped to a drugstore by Cleanbrush Products along with 17 nondefective ones.
a.) What is the probability the first two electric toothbrushes sold will be returned to the drugstore because they are defective?
b.) What is the probability the first two electric toothbrushes sold will not be defective?© BrainMass Inc. brainmass.com October 16, 2018, 5:45 pm ad1c9bdddf
a) Before the first unit is sold, there are 3 units among 18 that are defective. Therefore, there is a 3/18 (=0.1666) probability that the first toothbrush will be defective.
Once the first defective toothbrush has been sold, there are 2 ...
In this solution, explanation is provided along with a calculation of probability, and an Excel file is attached.
6 probability and statistics questions
CH3 Problem 50
The mean income of a group of sample observations is $500; the standard deviation is $40. According to Chebyshev's theorem, at least what percent of the incomes will lie between $400 and $600?
CH3 Problem 62
The Citizens Banking Company is studying the number of times the ATM located in a Loblaws Supermarket at the foot of Market Street is used per day. Following are the numbers of times the machine was used over each of the last 30 days. Determine the mean number of times the machine was used per day.
83 64 84 76 84 54 75 59 70 61
63 80 84 73 68 52 65 90 52 77
95 36 78 61 59 84 95 47 87 60
CH5 Problem 28
Three defective electric toothbrushes were accidentally shipped to a drugstore by Cleanbrush Products along with 17 nondefective ones. What is the probability the first two electric toothbrushes sold will be returned to the drugstore because they are defective?
CH5 problem 78
The state of Maryland has license plates with three numbers followed by three letters. How many different license plates are possible?
CH7 problem 20
The mean starting salary for college graduates in the spring of 2004 was $36,280. Assume that the distribution of starting salaries follows the normal distribution with a standard deviation of $3,300. What percent of the graduates have starting salaries:
a. Between $35,000 and $40,000?
b. More than $45,000?
c. Between $40,000 and $45,000?
CH7 problem 40
It is estimated that 10 percent of those taking the quantitative methods portion of the CPA examination fail that section. Sixty students are taking the exam this Saturday.
a. How many would you expect to fail? What is the standard deviation?
b. What is the probability that exactly two students will fail?
c. What is the probability at least two students will fail?