Answer:
a
The null hypothesis is

The alternative hypothesis

b
The 95% confidence interval is

Explanation:
From the question the we are told that
The population mean is

The sample size is n = 30
The sample mean is

The standard deviation is

Given that the confidence level is
then the level of significance is mathematically represented as


=>

Next we obtain the critical value of
from the normal distribution table
The value is

Generally the margin of error is mathematically represented as

substituting values


The 95% confidence interval confidence interval is mathematically represented as

substituting values

