The Cedar Rapids Gazette (November 20, 1999) reported the following information on compliance with child restraint laws for cities in Iowa: that a newborn baby is female, given that the ultrasound predicted the baby would be female.
Number of Number Children Properly
City Observed Restrained
Cedar Falls 210 173
Cedar Rapids 231 206
Dubuque 182 135
Iowa City (city) 175 140
Iowa City (interstate) 63 47
a. Use the given information to estimate the probability that a newborn baby is male, given that the ultrasound predicted the baby would be male.
b. Based on your answers to Parts (a) and (b), do you think ultrasound is equally reliable for predicting gender for boys and for girls? Explain.