Question

My notes ask your teacher practice another suppose that 30% of all students who have to buy a text for a particular course want a new copy (the successes!), whereas the other 70% want a used copy. consider randomly selecting 15 purchasers.

in USE SALT (a) What are the mean value and standard deviation of the number who want a new copy of the book? (Round your standard deviation to two decimal places.) mean students standard deviation students

Answer 1

To find the mean and standard deviation of the number of students who want a new copy of the book, we can use the binomial distribution formula. In this case, the number of trials (n) is 15, and the probability of success (p) is 0.3.

(a) The mean value (µ) and standard deviation (σ) of a binomial distribution can be calculated using the following formulas:

Mean (µ) = n * p
Standard deviation (σ) = √(n * p * (1 - p))

Step 1: Calculate the mean value.
Mean (µ) = 15 * 0.3 = 4.5 students

Step 2: Calculate the standard deviation.
Standard deviation (σ) = √(15 * 0.3 * (1 - 0.3))
σ = √(15 * 0.3 * 0.7)
σ ≈ 1.93 students (rounded to two decimal places)

So, the mean value of students who want a new copy of the book is 4.5 students, and the standard deviation is approximately 1.93 students.