I need a little help with the following statistics problem:
According to a market research firm, 56% of all residential telephone numbers in Los Angeles are unlisted. A telephone sales firm uses random digit dialing equipment that dials residential numbers at random, whether or not they are listed in the telephone directory. The firm calls 548 numbers in Los Angeles. What are the mean and standard deviation of the proportion of unlisted numbers in the sample?
I’m familiar with determining the mean given a set of numbers but I’m not really sure what to do with this. Can anyone help?
n = 548; p = 0.56; q = 0.44; x = 1
formulas:
μ = (n p) = 306.88; σ² = ( n p q ) = 135.0272; σ = √( n p q ) = 11.6201