The following five values are a sample: 20, 18, 13, 15, and 4.

a.Compute the variance.(Round the final answerto 1 decimal place.)

Variance

b.Determine the sample standard deviation.(Roundthe final answer to 4 decimal places.)

Sample standard deviation

1. A study of 238 advertising firms revealed their income after taxes:

Income after TaxesNumber of Firms

Under $1 million 122

$1 million to $20 million 76

$20 million or more 40

a.What is the probability an advertising firm selected at random has under $1 million in income after taxes?(Round the final answer to 2 decimal places.)

Probability

b-1.What is the probability an advertising firm selected at random has either an income between $1 million and $20 million, or an income of $20 million or more?(Round the final answer to 2 decimal places.)

Probability

b-2.What rule of probability was applied?

Rule of Probability

(Click to select)

Either

Rule of complements

Special rule of addition