Answer:
a) H0 : u = 28.5%
H1 : u < 28.5%
b) critical value = - 1.645
c) test statistic Z= - 1.41
d) Fail to reject H0
e) There is not enough evidence to support the professor's claim.
Step-by-step explanation:
Given:
P = 28.5% ≈ 0.285
X = 210
n = 800
Level of significance = 0.05
a) The null and alternative hypotheses are:
H0 : u = 28.5%
H1 : u < 28.5%
b) Given a 0.05 significance level.
This is a left tailed test.
The critical value =
The critical value = -1.645
c) Calculating the test statistic, we have:
Z = -1.41
d) Decision:
We fail to reject null hypothesis H0, since Z = -1.41 is not in the rejection region, <1.645
e) There is not enough evidence to support the professor's claim that the proportion of obese male teenagers decreased.