write my assignment 5579

Re: Normal Probability Distribution Question

The speed of cars passing through a checkpoint follows normal distribution with µ=62.6 miles per hour and σ=3.7 miles per hour. What is the probability that the next car passing will be between 61 and 70 miles per hour?

***I was able to complete the first half of the problem correctly. I can’t figure out how the values in the second half were obtained.***

(70-62.5)/3.7 = 2

(61-62.5)/3.7 = -.043

My answer key tells me that the answer is:

0.9772 – 0.3327 = 0.6445

P[-.043≤ z ≤ +2.0] = P[z≤+2.0] – P[z-.043]

P[-.043≤ z ≤ +2.0] = 0.9772-0.3327=0.6445

My calculations did not give me the values above. HOW did they come up with these values? I’ve obviously done something wrong.