Answer:
The test statistic for this situation is calculated using the following formula:
t = (Mean - Hypothesized Mean) / (Standard Error)
In this case, the hypothesized mean is the standard air pressure for an NFL football, which is 12.5 psi. The standard error is calculated as follows:
Standard Error = Standard Deviation / √(Sample Size)
Plugging in the values:
Standard Error = 0.40 psi / √(11) = 0.1225 psi
Now we can calculate the test statistic:
t = (11.1 psi - 12.5 psi) / 0.1225 psi = -1.40
Since the calculated test statistic is -1.40, it indicates that there is not a significant difference between the average air pressure of the footballs used by the New England Patriots and the standard air pressure for an NFL football.