Question

In 1990 a national vital statistics report indicated that about 2.2 % 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 532 teenage girls. Test an appropriate hypothesis and state your conclusion. Be sure the appropriate assumptions and conditions are satisfied before you proceed.

Answer 1

Conditions

And

So, both the conditions are satisfied

Now we can proceed with our hypothesis testing

we have p = 2.2% or 2.2/100 = 0.022 and sample proportion

calculation for z statistic

z =

setting the given values, we get

z=

this gives z = -1.1

now, using the normal distribution table for two tailed hypothesis with z value of -1.1, we get

p value = 0.2713 which is insignificant

Thus,we can conclude that the rate of twin births is not the same amound very young mothers.

Fail to reject the null hypothesis.