Calculate the standard deviation var rounded three decimal places

Solved Step by Step With Explanation- Email Tracking Stats: 30 Emails

Questions

(b) What are the variance and standard deviation for the number of these emails that are tracked? (Round your answers to three decimal places.)

Var(x)=

To find the expected number of tracked emails, variance, and standard deviation for the number of tracked emails among 30 randomly selected received emails, we can use the concept of the binomial distribution.

(a) Expected Number:

p is the probability of success (the probability that an email is tracked), which is 40% or 0.40 in decimal form.

E[X] = 30 * 0.40 = 12

σ = √Var(X)

Where:

σ = √Var(X) = √7.2 ≈ 2.683 (rounded to three decimal places)

So, the variance is approximately 7.200, and the standard deviation is approximately 2.683 for the number of tracked emails among 30 received emails.