A consumer agency wanted to investigate if four insurance companies differed with regard to the premiums they charge for auto insurance. The agency randomly selected a few auto drivers who were insured by each of these four companies and had similar driving records,autos, and insurance policies. The following table gives the premiums paid per month by these drivers insured with these four insurance companies.

Question

A consumer agency wanted to investigate if four insurance companies differed with regard to the premiums they charge for auto insurance. The agency randomly selected a few auto drivers who were insured by each of these four companies and had similar driving records,autos, and insurance policies. The following table gives the premiums paid per month by these drivers insured with these four insurance companies. 
 
Company A - 75 83 68 52 
 
Company B - 59 75 100 
 
Company C - 65 70 97 90 73
 
Company D - 76 60 52 58
 
Using the 5% significance level, test the null hypothesis that the mean auto insurance premium paid per month by all drivers insured by each of these four companies is the same.