Which of the following statements is true?
$P: 17$ is a prime number $Q: 23$ is a composite number

Step 1 ：The problem is asking us to determine the truth value of two statements: P, which states that 17 is a prime number, and Q, which states that 23 is a composite number.

Step 2 ：A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. A composite number is a positive integer that has at least one positive divisor other than one or itself.

Step 3 ：We can determine the truth value of these statements by checking if 17 and 23 meet the criteria for being prime and composite numbers, respectively.

Step 4 ：17 is indeed a prime number and 23 is not a composite number. Therefore, statement P is true and statement Q is false.

Step 5 ：\(\boxed{\text{The statement } P \text{ is true and the statement } Q \text{ is false.}}\)