Question

According to an article in Newsweek, the natural ratio of girls to boys is 100:105. In China, the birth ratio is 100:114 (46.7% girls). Suppose you don't believe the reported figures of the percent of girls born in China. You conduct a study. In this study, you count the number of girls and boys born in 150 randomly chosen recent births. There are 59 girls and 91 boys born of the 150. Based on your study, do you believe that the percent of girls born in China is 46.7? Conduct a hypothesis test at the 5% level

• What is the test statistic? (If using the z distribution round your answers to two decimal places, and if using the t distribution round your answers to three decimal places.)
  

• What is the p-value?

Answer 1

n= 150, x=59 p=46.7% =0.467, = 5% =0.05

a)

Ho: p =  0.467

Ha: p 0.467

b)

z = -1.8084

rounding to 2 decimals

Test statistics = -1.81

c)

calculate P-Value for two tailed test

P-Value = 2 * P(z < -1.81)

using normal z table we get

P(z < -1.81) = 0.0351

P-Value = 2 * 0.0351

P-Value = 0.0702

d)

since ( P-Value = 0.0702) > (= 0.05 )

Failed to reject null hypothesis.

e) Yes, we believe.

Therefore there is enough sufficient evidence to believe that the percent of girls born in China is 46.7