A researcher knew that before cell phones, a person made on average 3.1calls per day. He believes that the number of calls made per day today is different. He selects a random sample of 32individuals who use a cell phone and asks them to keep track of the number of calls that they made on a certain day. The mean was 3.3.

At 0.05 level of significance, is there enough evidence to support the researcher's claim? The standard deviation for the population found by a previous study is 0.6.

Assume that the variable is normally distributed.

State the hypotheses