Exam 3 Review; problem 6

  • A dinosaur is one of the many toys manufactured by Big Toy Corporation. The assembly times for this toy follow a normal distribution with a mean of 25 minutes and a standard deviation of 9 minutes. The factory closes at 6 P.M. every day. If one worker starts to assemble a dinosaur at 5:30 P.M., what is the probability that she will finish this job before the company closes for the day?

Step 1: First, we need to find our mean, standard deviation, and x. The mean and standard deviation are given to us in thew problem, but I found x because she needed to finish her project by 6 and she started at 5:30, so that would give her 30 minutes.

Step 2: Then, I plugged the values in the equation for Normal Distributions, which is: z = (x-mean)\(standard deviation), which is (30-25)/(9). That works ouot to be (5)/(9), which comes out to 0.555555556.

Step 4: Next, I rounded my answer. Rounding is very important for these type of problems. I rounded z=0.555555556 to z=0.56.

Step 5: After, I looked z=0.56 up in the table and the probability in the chart was .7123.


I hope you all are able to understand this problem. I did take a picture, but unfortunately, I’m having trouble uploading it. I’ll probably upload it in the near future once I get technical assistance. Study hard! Godd luck on the final!

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