A sample of 77 individuals working at specific construction site office was chosen at random. The noise level (dBA) experienced by each individual was determined. The site manager is curious if there is evidence that average noise level experienced by all workers is less than 70 dBA. Carry out an analysis. Employ a significance level of 0.05.
a. Comprise a plot of the data.
b. Is there visual evidence that true mean is less than 70 dBA? Explain. Must include context.
c. Describe the null and alternative hypothesis to answer the manager's question of interest.
d. Compute the test statistic by hand and obtain a p-value by table. Show work.
e. Compute the 95% Confidence Interval by hand. Show work.
f. Obtain p-value from t test and confidence interval. Are your answers different than d and e?