Professional tennis player Andre Agassi is known for having a fast serve; his fastest recorded serve ever is 157.2 miles per hour. Asample of 10 of Isner's serves is collected, and you observe the following speeds in miles per hour: 142, 143, 143, 144, 146, 146, 146, 147, 147, and 150. The standard deviation of his serve speed is known to be

= 3.

Assuming that the distribution of his serve speed follows a normal distribution, construct a 90% confidence interval for the true mean of his serve speed.