Statistics ,

in a table of random digits, each digit is to occur with a probability of 0.1.
a) a student examines a list of 200 random digits and counts only eleven 4s and thus claims that the table is not really random. explain the error in the student's thinking.
b) how many 7s would you expect to find in a random digit table consisting of 1,000 digits?

i think b) might be 100 because it says the probability of every number is 0.1, which is 10%, and 10% of 1,000 is 100. can someone and explain both of these? so !

The westins and the shermans live in the same city and pay the same sales tax rate, and both families made $14,000 in taxable purchases last year. if the westins made $86,000 and the shermans made $33,000 last year, is the sales tax in their city an example of a regressive tax? yes, because the westins and the shermans both paid the same sales tax rate. b. no, because the shermans paid a higher percentage of their income in sales tax than the westins did. c. no, because the westins and the shermans both paid the same sales tax rate. d. yes, because the shermans paid a higher percentage of their income in sales tax than the westins did.