AP Statistics #11-20

Normal Curve (11)
A soft drink dispenser can be adjusted to deliver any fixed number ounces.  If the machine is operating with a standard deviation in delivery equal to 0.3 ounce, what should be the mean setting so that a 12-ounce cup will overflow less than 1% of the time?  Assume a normal distribution for ounces delivered.

• A) 11.23 ounces
• B) 11.30 ounces
• C) 11.70 ounces
• D) 12.70 ounces

Sampling Methods (12)

An insurance company wishes to study the number of years drivers in a large city go between automobile accidents. They plan to obtain and analyze the data from a sample of drivers. Which of the following is a true statement?

• A) A reasonable time-and-cost-saving procedure would be to use systematic sampling on an available list of AAA (automobile Association of America) members in the city.

• B) A reasonable time-and-cost-saving procedure would be to randomly choose families and include all drivers in each of these families in the sample.

• C) To determine the mean number of years between accidents, randomness in choosing a sample of drivers is not important as long as the sample size is very large.

• D) None of the statements are true statements.

Probability (13)
The probability that a person will show a certain gene-transmitted trait is 0.8 if the father shows the trait and 0.06 if the father doesn't show the trait.  Suppose that the children in a certain community come from families 25% of which the father shows the trait.  Given that a child shows the trait, what is the probability that her father shows the trait?

• A) 0.245
• B) 0.250
• C) 0.750
• D) 0.816

Normal Curve (15)
If all the values of a data set are the same, all of the following must equal zero except for which one?

• A) Mean
• B) Standard deviation
• C) Variance
• D) Interquartile Range

Sampling Methods (17)
A company has 1000 employees evenly distributed throughout 5 assembly plants.  A sample of 30 employees is to be chosen as follows.  Each of the 5 managers will be asked to place the 200 time cards of their respective employees in a bag, shake them up, and randomly draw out 6 names. The 6 names from each plant will be put together to make up the sample.  Will this method result in a simple random sample of the 1000 employees?

• A) Yes, because every employee has the same chance of being selected.
• B) Yes, because every plant is equally represented.
• C) No, because the plants are not chosen randomly.
• D) No, because not every group of 30 employees has the same chance of being selected.

Probability (18)
Given that P(E) = 0.32, P(F) = 0.15, and P(E∩F) = 0.048, which of the following is a correct conclusion?

• A) The events E and F are both independent and mutually exclusive.
• B) The events E and F are neither independent nor mutually exclusive.
• C) The events E and F are independent but not mutually exclusive.
• D) The events E and F are independent, but there is insufficient information to determine whether or not they are mutually exclusive.

Normal Curve (19)
The number of leasable square feet of office space available in a city on any given day has a normal distribution with mean 640,000 square feet and standard deviation 18,000 square feet.  What is the interquartile range for this distribution? (Hint: you will need to find the z-scores of Q1 and Q3 to start the problem)

• A) 652,000 - 628,000
• B) 658,000 - 622,000
• C) 667,000 - 613,000
• D) 676,000 - 604,000

Descriptive Statistics Stem & Leaf (20)
Consider the following back to back stemplot.  Which of the following is a correct statement?

• A) The distributions have the same mean.
• B) The distributions have the same median.
• C)The IQR of the distribution to the left is 20 greater than the IQR of the distribution to the right,
• D) The distributions have the same variance.