AP Stat Unit 6

The z-score represents.....

• the amount of standard deviations a data value is above or below the mean.

• the percentile the data value is above or below the mean.

• the amount of standard deviations a data value is above or below the median.

• the percent the data value is above or below the mean.

The distances male long jumpers for State College jump are approximately normal with a mean of 263 inches and a standard deviation of 14 inches.  
Suppose a male long jumper's jump ranked in the 75th percentile.  How long was his jump?

• 0.67 inch

• 263 inches

• 272.44 inches

• 277.25 inches

The probability distribution for the number of heads in four tosses of a coin is given above. The probability of getting at least one tail in four tosses of a coin is

• 15/16

• 4/16

• 1/16

• 14/16

According to the U.S. Census, the proportion of adults in a certain county who owned their own home was 0.71. An SRS of 100 adults in a certain section of the county found that 65 owned their home. Which one of the following represents the approximate probability of obtaining a sample of 100 adults in which fewer than 65 own their home, assuming that this section of the county has the same overall proportion of adults who own their home as does the entire county?

• a

• b

• c

• d

Records from a random sample of dairy farms yielded the information above on the number of male and female calves born at various times of the day.
What is the probability that a randomly selected calf was born in the night or was a female?

• 369/513

• 261/513

• 223/513

• 116/233

A grocery chain runs a prize game by giving each customer a ticket that may win a prize when the box is scratched off. Printed on the ticket is a dollar value ($500,$100, $25) or the statement “This ticket is not a winner.” Monetary prizes can be redeemed for groceries at the store. Here is the probability distribution above represents the amount won on a randomly selected ticket.
Which of the following are the mean and standard deviation, respectively, of the winnings?

• $15.00, $2900.00

• $15.00, $53.85

• $15.00, $26.93

• $156.25, $53.85

The five-number summary for a data set is given by min = 5, Q₁ = 18, median = 20, Q₃ = 40, max = 75. If you wanted to construct a boxplot for the data set (that is, one that would show outliers, if any existed), what would be the maximum possible length of the right-side “whisker”?

• 35

• 40

• 45

• 53

In a certain large population of adults, the distribution of IQ scores is strongly left-skewed with a mean of 122 and a standard deviation of 5. Suppose 200 adults are randomly selected from this population for a market research study. The distribution of the sample mean of IQ scores is

• exactly Normal with mean 122 and standard deviation 5.

• exactly Normal with mean 122 and standard deviation 0.35.

• approximately Normal with mean 122 and standard deviation 5.

• approximately Normal with mean 122 and standard deviation 0.35.

Suppose we roll a fair die four times. The probability that a 6 occurs on exactly one of the rolls is

• 6(1/6)^2(5/6)^2

• 4(1/6)^1(5/6)^3

• 4(1/6)^3(5/6)^1

• 1(1/6)^0(5/6)^4

The number of unbroken charcoal briquets in a 20-pound bag filled at the factory follows a Normal distribution with a mean of 450 briquets and a standard deviation of 20 briquets. The company expects that a certain number of the bags will be underfilled, so the company will replace for free the 5% of bags that have too few briquets. What is the minimum number of unbroken briquets the bag would have to contain for the company to avoid having to replace the bag for free?

• 404

• 418

• 411

• 425