Question

In 1995 a national vital statistics report indicated that about 2 % of all births produced twins. Is the rate of twin births the same among very young​ mothers? Data from a large city hospital found only 8 sets of twins were born to 510 teenage girls. Test an appropriate hypothesis and state your conclusion. Be sure the appropriate assumptions and conditions are satisfied before you proceed.

A. Determine the z test statistic (Round to two decimal places as needed)

B. Find the P-Value (Round to three decimal places as needed)

Answer 1

Solution :

Given that,

= 0.02

1 - = 0.98

n = 510

x = 8

Point estimate = sample proportion = = x / n = 0.016

This a left (One) tailed test.

A)

Ho: p = 0.02

Ha: p < 0.02

A)

Test statistics

z = ( - ) / *(1-) / n

= ( 0.016 - 0.02) / (0.02*0.98) / 510

= -0.65

B)

P-value = P(Z<z)

= P(Z <-0.65)

= 0.258