Answers created by Jeffrey W.

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• What is z value corresponding to the 65th percentile of the standard normal distribution?
  
• Assume that IQ scores are normally distributed, with a mean #mu# of 100 and standard deviation #sigma# of 15. What is the probability that a randomly selected person has an IQ score between 105 and 110?
  
• What is the meaning of conditional probability?
  
• If we are interested in calculating the probability that a first success occurs on the 6th trial, what do we know about the outcomes of the first 5 trials?
  
• In a jar are 10 marbles: 4 red, 5 blue, and 1 yellow. Why can we use the special addition rule to calculate the probability that a single marble drawn from the jar will be either red or yellow? What is the probability?
  
• Use your common sense to answer this question. Are the events "Rain" and "Having a Car Accident" independent or dependent?
  
• What must the frequencies in a frequency distribution add up to?
  
• You stand at the basketball free-throw line and make 30 attempts at at making a basket. You make 3 baskets, or 10% of your shots. Is it accurate to say that three weeks later, when you stand at the free-throw line, that the probability of making a basket on your first attempt is 10%, or .10?
  
• You weigh 30 people who exercise every day, and you weigh 30 people who do not get regular exercise. The exercise group has a mean weight which is 22 pounds less than the non-exercise group's mean. Can you conclude that exercise causes people to weigh less?
  
• Assume that a gallon of milk bought at the store goes bad some time in the interval from 5 days to 10 days after purchase. What is the standard deviation of this distribution?
  
• The last 3 times you went to the dentist for your 6-month checkup, it rained as you drove to her office. What is the probability that it will rain while you are driving to today's dental appointment?
  
• How is a z-score useful in comparing two different distributions?
  
• What is wrong with the answer choices to the question: How much did you like your statistics course this semester? (A.) Not at all (B.) A lot (C.) It was awesome!
  
• If a histogram is unimodal and symmetric, what well-known curve will the histogram approximate?
  
• What is the probability of an impossible event?