## Elementary Statistics (12th Edition)

a) For $H_0$, $p=0.5$; For $H_1$, $p\gt0.5$ b) $0.01$ c) Normal d) Right-tailed e) $1.00$ f) $0.1587$ g) $2.33$ h) $0.01$
a) The null hypothesis is the average fraction of girls, which is $0.5$, and the alternative hypothesis is that more than 50 percent of births are girls, which is $p\gt0.5$. b) $α$ is the significance level, which the problem says is $0.01$. c) We can see that the sample distribution of the sample statistic is a normal distribution. d) There are more girls in the survey, so the two-test is right tailed. e) The problem says that the sample statistic is $1.00$. f) Using the table of z-scores, we can find that: $P=1−0.8413=0.1587$ g) Using the table of z-scores, we can find that the critical value is $2.33$. h) The significance level is $0.01$, hence the area of the critical region is $0.01$.