Absolute blinking speed LED potentiometer arduino

int input = A0;

float analogValue = 0;

float analogValueMax;
float analogValueMin = 200000;

float analogRange = 0;

float maxInterval = 500;

void setup() {
  pinMode(13, OUTPUT);
  Serial.begin(9600);
  Serial.println("Hello World");
}

void loop() {
  analogValue = analogRead(input);
  Serial.print("anV");
  Serial.println(analogValue);

  if (analogValue > analogValueMax) {
    analogValueMax = analogValue;
  } else if (analogValue < analogValueMin) {
    analogValueMin = analogValue;
  }

  Serial.print("anVMAX  ");
  Serial.print(analogValueMax);
  Serial.print("    anVMIN  ");
  Serial.println(analogValueMin);


  analogRange = analogValueMax - analogValueMin;

  float interval = ((analogValue - analogValueMin) / analogRange) * maxInterval;
  Serial.print("    ***INTERVAL***  ");
  Serial.println(interval);

  digitalWrite(13, HIGH);
  delay(interval);
  digitalWrite(13, LOW);
  delay(interval);

}