Week 3 Individual Practice Exercises
I want to revisit an exercise that we went over in class last week as a practice. There was a little
confusion about the process for finding a solution, but it is a good illustration of a continuous probability
The Alioto Fish Market on the San Francisco Pier wants to determine the probability that a randomly
selected blue crab has a weight greater than 1 kg. Assume that the distribution of weights (kg) of
adult blue crabs is normally distributed with a population mean (μ) of 0.8 kg and a standard
deviation (σ) of 0.3 kg. What is the probability that a randomly selected adult blue crab will
weigh more than one kilogram?
Mean Weight = 0.8 kg
Standard Deviation =0.3
Weight target = 1 kg
Step one requires you to find the z score for this problem using the z score formula:
1.0 minus 0.8 divided by the standard deviation (0.3) yields a z-score of 0.67
Now, look up the numbers 0.67 + and minus which yields scores of .7486 (upper) and .2514
Since we are looking trying to find the probability of a randomly selected blue crab weighing
more than 1 kg, the answer is as follows:
Therefore, the probability of finding a randomly selected blue crab weighing more than 1 kg
is .2514. Not very high.
The following questions and exercises are directly related to the achievement of the objectives stated
for Weeks 2 and 3. Please answer the items below and submit them as part of your Week 3 Individual
Southwest Airlines wanted to improve its on-time arrival in the month of July. Its
average time for June was 10.45 minutes per flight with a standard deviation of 1.87 minutes.
What is the probability that their on-time arrivals will be less than nine minutes in July?
McBurgers Restaurant claimed that they could provide anything on the menu in three
minutes. A survey of 1000 customers yielded the following data. Mean 5.71 minutes with a
standard deviation of 1.02 minutes.
What is the probability that McBurgers could provide a meal in less than 4
What is the probability that McBurgers could provide a meal in more than
3. Which statement is not true about a binomial distribution:
A. _____ Each trial can result in just two possible outcomes.
B. _____ the number of times an event occurs in an interval
C. ______ n represents repeated trials
D. ______ The probability of success, denoted by P, is the same on every trial.
The revenues for one week at the Bon Appetite Café are as follows:
Calculate a confidence interval at the 99% level and explain what it might represent to the
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