The length of time to find a parking space with mean of 6 min, standard deviation of 2 min. Probability it takes at least 9 min to find parking spot

Answer 1

x = time to find parking space

want to find P(x > 9), where x is mean 6 std dev 2.

convert inequality to z mean 0 and std dev 1 where z = (x - mean)/SD.

P(x > 9) = P( z > (9 - 6)/2) = P(z > 1.5) = 1 - P(z < 1.5) = 1 - 0.9332 = 0.0668.