AP Statistics Unit 5

P(Freshman or Pizza):

• 27/50

• 4/50

• 3/50

• 2/11

Given P(A) = .8 and P( B| A) = .3, find P( A and B).

• 2.6

• .12

• .24

• .38

If A and B are independent, which statement must be true?

• P(A∩B) = 0

• P(A|B) = P(A)

• P(A∪B) = 0

• P(A) + P(B) = 1

Owners of a chain of ice cream shops recently examined sales figures and noticed that on a randomly selected day, 21 of 103 ice cream cus­tomers from their shop located in the eastern part of the state ordered soft-serve ice cream, while 29 of 132 ice cream customers from their shop located in the western part of the state ordered soft-serve ice cream. Construct a 95% confidence interval to find the difference in proportions of customers who favor soft-serve ice cream in the two parts of the state.

• 
• 
• 
• 

The proportion of orange salamanders along a certain stream is known to be 10%. Use a Normal model to approximate the probability that, for a sample of 100 salamanders along this stream, at least 20 of them are orange.

• .0004

• .3707

• .9996

• .6293

The manager of an orchard expects about 70% of his apples to exceed the weight requirement for "Grade A" designation. At least how many apples must he sample to be 90% confident of estimating the true proportion within ± 4%?

• 356

• 505

• 89

• 23

Owners of a chain of ice cream shops recently examined sales figures and noticed that on a randomly selected day, 21 of 103 ice cream customers from their shop located in the eastern part of the state ordered soft-serve ice cream, while 29 of 132 ice cream customers from their shop located in the western part of the state ordered soft-serve ice cream. Is there a significant difference in the proportions of customers who favor soft-serve ice cream in the eastern and western parts of the state?

• There is a significant difference at the 0.10 level, but not at the 0.05 level.

• There is a significant difference at the 0.05 level, but not at the 0.01 level.

• There is a significant difference at the 0.01 level, but not at the 0.001 level.

• There is no significant difference at the 0.10 level.

A major university expresses 95% confidence that about 90% to 93% of its students find employment in their field within one year of graduation. What is the margin of error implied in this statement?

• 1%

• 1.5%

• 3%

• 6%

In the diagram, Region II is the rejection region for the null hy­pothesis. The area of which non-overlapping region(s) represents the probability of committing a Type II Error?

• Region I and Region III

• Region I and Region V

• Region II

• Region II and Region IV

For a simple random sample of 100 cars of a certain popular model in 2012, it was found that 20 had a certain minor defect in the brakes. For an independent SRS of 400 cars of the same model in 2009, it was found that 50 had the same defect. A 90% confidence interval for the difference between 2012 and 2009 is

• 0.075 ± 0.085

• 0.075 ± 0.071

• 0.075 ± 0.043

• 0.075 ± 0.142