Question

Although many new moms will nurse their new babies in the beginning, the Pediatrics Associa-tion believes that 50% of moms are still nursing their babies by the time the babies are six months old. The La Leche Society believes that this proportion is less than 50% and thus believes more edu-cational information should be given to new moms to encourage the mothers to nurse for the first year of their child’s life. A random sample of 425 new moms was obtained and 200 were still nurs-ing their child at six months of age. At the 2.5% significance level, what conclusion can be reached?

Answer 1

H0: p = 0.50

Ha: p < 0.50

Sample proportion = 200 / 425 = 0.4706

Test statistics

z = ( - p) / sqrt (p( 1 - p) / n )

= (0.4706 - 0.50) / sqrt ( 0.50 * 0.50 / 425)

= -1.21

This is test statistics value.

p-value = P(Z < z)

= P(Z < -1.21)

= 0.1131

Since p-value > 0.025 significance level, do not reject H0 .

We conclude at 0.025 level that we fail to support the claim.