The Test for a Group Mean or One Sample t-Test

Let's recall, in Chap. 3 we learned about and calculated the arithmetic mean. For example, we found out for our companies that they have grown by an average of 7.1% over the last 5 years, that they spend an average of 19.81% of their revenue on marketing and an average of 4.65% on innovation. Furthermore, we know that the company founders are on average 34.25 years old and that they have an industry professional experience of 7.42 years. But do these results also apply to the population? We can test this.