Question

2. A random sample of 25 male runners has a mean of ̄x= 60 and standard deviation s = 3 kilograms(kg). Suppose that the mean weights of male runners follow a normal distribution with unknown mean μ and unknown standard deviation σkg. Find a 90% confidence interval for μ. (10 pts.)

Answer 1

Answer:

n= 25,   = 60 , s= 3

c= 90 %

formula for confidence interval is

Where tc is the t critical value for c= 90% with df=n-1 = 25-1 = 24

using t table we get critical value as

tc = 1.711

58.9734 <    < 61.0266

58.97 <    < 61.03

We get confidence interval as ( 58.97 , 61.03 )