DATSET link (Zingaro_Company)

https://drive.google.com/file/d/1inyaM3E4fwoP-Sykjk3k89ek-p-6xbxg/view?usp=sharing

Zingaro stone printing is a company that specializes in printing images or patterns on polished or unpolished stones. However, for the optimum level of printing of the image the stone surface has to have a Brinell's hardness index of at least 150. Recently, Zingaro has received a batch of polished and unpolished stones from its clients. Use the data provided to answer the following (assuming a 5% significance level);

1 Earlier experience of Zingaro with this particular client is favorable as the stone surface was found to be of adequate hardness. However, Zingaro has reason to believe now that the unpolished stones may not be suitable for printing. Do you think Zingaro is justified in thinking so?

2 Is the mean hardness of the polished and unpolished stones the same?