In: Statistics and Probability
Identify the null and alternative hypothesis(in symbolic and sentence form), test statistic, P-value(or critical values), conclusion about the null hypothesis, and final conclusion that addresses the original claim (Don’t just say Reject the null hypothesis or fail to reject the null hypothesis).
5. A simple random sample of 15-year old boys from one city is obtained and their weights (in pounds) are listed below. Use a 0.01 significance level to test the claim that these sample weights come from a population with a mean equal to 147 lb. Assume that the standard deviation of the weights of all 15-year old boys in the city is known to be 16.7 lb.
146 140 160 151 134 189 157 144 175 127 164
5.
Given that,
population mean(u)=147
standard deviation, σ =16.7
sample mean, x =153.3636
number (n)=15
null, Ho: μ=147
alternate, H1: μ!=147
level of significance, α = 0.01
from standard normal table, two tailed z α/2 =2.576
since our test is two-tailed
reject Ho, if zo < -2.576 OR if zo > 2.576
we use test statistic (z) = x-u/(s.d/sqrt(n))
zo = 153.3636-147/(16.7/sqrt(15)
zo = 1.476
| zo | = 1.476
critical value
the value of |z α| at los 1% is 2.576
we got |zo| =1.476 & | z α | = 2.576
make decision
hence value of |zo | < | z α | and here we do not reject
Ho
p-value : two tailed ( double the one tail ) - ha : ( p != 1.476 )
= 0.14
hence value of p0.01 < 0.14, here we do not reject Ho
ANSWERS
---------------
null, Ho: μ=147
alternate, H1: μ!=147
test statistic: 1.476
critical value: -2.576 , 2.576
decision: do not reject Ho
p-value: 0.14
we do not have enough evidence to support the claim that these
sample weights come from a population with a mean equal to 147
lb.