# Phone Survey Company Probabilities

A company has 95% customer satisfaction. The company gets info by surveying customers over the phone. The satisfaction of each customer is considered to be independent from the others. If 40 customers are surveyed at random, what is the type of probability distribution is the model for this solution?

What is the expected number of satisfied customers in this group?

What is the variance for the satisfied customers?

What is the probability that 30 of the 40 will respond that they are satisfied?

What is the probability that between 35 and 38 (including 35 & 38) customers are satisfied?

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#### Solution Preview

The type of probability distribution is Binomial distribution B(n, p), where n = 40, p = 95% = 0.95.

When n is big enough, B(n, p) is approximate the normal ...

#### Solution Summary

Calculations shown find the expected number of satisfied customers and other probability statistics for a phone survey company.