to estimate p, the proportion of all newborn babies who are male, the gender of 10,000 newborn babies was noted. if 5106 were male determine a) a 90 percent confidence interval estimate of p b) a 99 percent confidence interval estimate of p?

Answer 1

A scratch-card costs 5¤ and has two possible prizes. There is a 10% chance you get 5¤ back
and
a 1% chance you get 100¤. In all other cases, you get nothing. Let X denote your net winnings,
i.e, (X = prize - cost). What are the expectation and standard deviation of X?

Answer 2

1200 and 200