Chapter 5 Review

A package delivery service claims that no more than 5 percent of all packages arrive at the address late. Assuming that the conditions for the binomial hold, if a sample of size 10 packages is randomly selected and the 5 percent rate holds, what is the probability that more than 2 packages will be delivered late?

0.0115

Previous research shows that 60 percent of adults who drink non-diet cola prefer Coca-Cola to Pepsi. Recently, an independent research firm questioned a random sample of 25 adult non-diet cola drinkers. That chance that 20 or more of these people will prefer Coca-Cola is:

0.0294.

A package delivery service claims that no more than 5 percent of all packages arrive at the address late. Assuming that the conditions for the binomial hold, if a sample of size 10 packages is randomly selected, and the 5 percent rate holds, what is the probability that exactly 2 packages in the sample arrive late?

0.0746

A sales rep for a national clothing company makes 4 calls per day. Based on historical records, the following probability distribution describes the number of successful calls each day: Successful Calls Probability 0 0.10 1 0.30 2 0.30 3 0.20 4 0.10 Based on this information, the probability that the sales rep will have a total of 2 successful calls in a two-day period is:

0.15

The following probability distribution has been assessed for the number of accidents that occur in a Midwestern city each day: Accidents Probability 0 0.25 1 0.20 2 0.30 3 0.15 4 0.10 The probability of having less than 2 accidents on a given day is:

0.45

Consider the following two probability distributions: Image Which of the following is an accurate statement regarding these two distributions?

Distribution A has a higher variance.

Which of the following statements is incorrect?

The mean of the probability distribution is equal to the square root of the variance.

Which of the following is not a condition of the binomial distribution?

The standard deviation is equal to the square root of the mean.

The Vardon Exploration Company is getting ready to leave for South America to explore for oil. One piece of equipment requires 10 batteries that must operate for more than 2 hours. The batteries being used have a 15 percent chance of failing within 2 hours. The exploration leader plans to take 15 batteries. Assuming that the conditions of the binomial apply, the probability that the supply of batteries will contain enough good ones to operate the equipment is:

0.9832

The following probability distribution has been assessed for the number of accidents that occur in a Midwestern city each day: Accidents Probability 0 0.25 1 0.20 2 0.30 3 0.15 4 0.10 Based on this probability distribution, the standard deviation in the number of accidents per day is:

1.28

The following probability distribution has been assessed for the number of accidents that occur in a Midwestern city each day: Accidents Probability 0 0.25 1 0.20 2 0.30 3 0.15 4 0.10 Based on this distribution, the expected number of accidents in a given day is:

1.65

A sales rep for a national clothing company makes 4 calls per day. Based on historical records, the following probability distribution describes the number of successful calls each day: Successful Calls Probability 0 0.10 1 0.30 2 0.30 3 0.20 4 0.10 The expected number of successful sales calls per day is:

1.90

Many people believe that they can tell the difference between Coke and Pepsi. Other people say that the two brands can't be distinguished. To test this, a random sample of 20 adults was selected to participate in a test. After being blindfolded, each person was given a small taste of either Coke or Pepsi and asked to indicate which brand soft drink it was. If people really can't tell the difference, the expected number of correct identifications in the sample would be:

10.

The following probability distribution has been assessed for the number of accidents that occur in a Midwestern city each day: Accidents Probability 0 0.25 1 0.20 2 0.30 3 0.15 4 0.10 This distribution is an example of:

a discrete probability distribution.

Many people believe that they can tell the difference between Coke and Pepsi. Other people say that the two brands can't be distinguished. To test this, a random sample of 20 adults was selected to participate in a test. After being blindfolded, each person was given a small taste of either Coke or Pepsi and asked to indicate which brand soft drink it was. If people really can't tell the difference, the probability that fewer than 6 people will guess correctly is:

approximately 0.02