AP Statistics



AP Statistics

Coley/P. Myers/Wylder

(Chapter 14 Review) Name ____________________________________________

Multiple Choice (Questions #1-10) - Circle the answer of your choice.

1. A geneticist claims that four species of fruit flies should appear in the ratio 1:3:3:9. Suppose that a sample of 4000 flies contained 226, 764, 733, and 2277 flies of each species, respectively. At the 10% significance level, is there sufficient evidence to reject the geneticist's claim?

(a) The test proves the geneticist's claim.

(b) The test proves the geneticist's claim is false.

(c) The test doe not give sufficient evidence to reject the geneticist's claim.

(d) The test gives sufficient evidence to reject the geneticist's claim.

(e) The test is inconclusive.

2. A study was done to determine the effectiveness of varying amounts of vitamin C in reducing the number of common colds. A survey of 450 people provided the following information:

| |Daily amount of vitamin C taken |

| |None |500 mg |1000 mg |

|No colds |57 |26 |17 |

|At least one cold |223 |84 |43 |

Is there evidence of a relationship between catching a cold and taking vitamin C?

(a) The data prove that vitamin C reduces the number of common colds.

(b) The data prove that vitamin C has no effect on the number of common colds.

(c) There is significant evidence at the 1% significance level of a relationship between taking vitamin C and catching fewer colds.

(d) There is significance evidence at the 10% level, but not at the 1% significance level, of a relationship between taking vitamin C and catching fewer colds.

(e) There is not sufficient evidence at the 10% level of a relationship between taking vitamin C and catching fewer colds.

3. Amos Tversky and Thomas Gilovich, on their study on the "Hot Hand" in basketball (Chance, Winter 1989, page 20) found that in a random sample of games, Larry Bird hit a second free throw in 48 of 53 attempts after the free throw was missed, and hit a second free throw in 251 of 285 attempts after the first free throw was made. Is there significance evidence to say that the probability that Bird will make a second free throw is different depending on whether or not he made the first free throw?

(a) P < .001, so this is very strong evidence that the probability that Bird will make a second free throw is different depending on whether he made the first.

(b) P is between .001 and .01, so this is strong evidence that the probabilities are different.

(c) P is between .01 and .05, so this is moderate evidence that the probabilities are different.

(d) P is between .05 and .10, so there is some evidence that the probabilities are different.

(e) P > .10, so there is little or no evidence that the probabilities are different.

4. The following data was collected concerning food purchases at several sporting events:

| |Food Purchases |

| |Hot Dogs |Popcorn |No Purchase |

|Sport |Football |240 |80 |30 |

| |Basketball |50 |90 |10 |

What would be the appropriate procedure to attempt to determine if a relationship exists between sports and food purchases?

(a) goodness-of-fit test with 2 df

(b) multiple 2-sample proportion tests

(c) independence test with 2 df

(d) independence test with 6 df

(e) goodness-of-fit test with 6 df

5. Using the data from question #4, what is the expected number of hot dog purchases at basketball games?

(a) 203

(b) 50

(c) 83.3

(d) 87

(e) cannot be determined

6. In the following table, what value of n results in a table showing perfect independence?

|n |52 |

|35 |10 |

(a) 10

(b) 17

(c) 27

(d) 77

(e) 182

7. It is generally agreed that the use of the chi-squared distribution is appropriate when the:

(a) sample size is at least 30

(b) sample size is large enough so that all of the observed cell counts is at least 5

(c) sample size is large enough so that all of the expected cell counts is at least 5

(d) sample size is large enough so that at least one of the expected cell counts is at least 5

(e) sample size is large enough so that the average of the expected cell counts is at least 5

8. A surprising study of 1437 male hospital admissions reported in The New York Times (February 24, 1993, page C12) found that, of 665 patients admitted with heart attacks, 214 had vertex baldness, while of the remaining 772 non-heart-related admissions, 175 had vertex baldness. Is this evidence sufficient at the 5% significance level to say that there is a relationship between heart attacks and vertex baldness?

(a) Yes, because [pic] , while the critical value is 3.84.

(b) Yes, because [pic] , while the critical value is 3.84

(c) No, because [pic] , while the critical value is 3.84.

(d) No, because [pic], while the critical value is 7.81.

(e) Yes, because [pic]

, while the critical value is 7.81.

9. In a chi-squared test of H0 : the population distribution is normal with specified values of and that is based on a sample of n = 100 observations classified according to 10 class intervals, the test statistic has:

(a) 99 degrees of freedom

(b) 97 degrees of freedom

(c) 9 degrees of freedom

(d) 7 degrees of freedom

(e) the number of degrees of freedom cannot be determined without the data

10. Which of the following statements are true?

I. The chi-squared inference procedures deal with categorical variables.

II. The chi-squared distribution is symmetric.

III. A chi-squared independence test on a 2X2 table produces the same result as a two-tailed difference of proportions test.

(a) I only

(b) I and II only

(c) I and III only

(d) I, II, and III

(e) none of the above

Free Response (#11-13) - Show your work.

11. Five partners in a law firm brought in the following numbers of new clients during the past year.

|Partner |Jones |Smith |Brown |Allen |Cross |

|Number of new clients |35 |42 |22 |41 |30 |

Is there sufficient evidence at the 5% or 10% level of significance that the partners do not bring in equal numbers of new clients? Show your work.

12. The Colorado Rocky Mountain Rescue Service wishes to study the behavior of lost hikers. If more were known about the direction in which lost hikers tend to walk, then more effective search strategies could be devised. Two hundred hikers selected at random from those applying for hiking permits are asked whether they would head uphill, downhill, or remain in the same place if they became lost while hiking. Each hiker in the sample was also classified according to whether he or she was an experienced or novice hiker. The resulting data are summarized in the following table.

| |Direction |

| |Uphill |Downhill |Remain in Same Place |

|Novice |20 |50 |50 |

|Experienced |10 |30 |40 |

Do these data provide convincing evidence of an association between the level of hiking expertise and the direction the hiker would head if lost?

Give appropriate statistical evidence to support your conclusion.

13. The following grades were earned by students in three teachers' classes.

| |Grade |

| |A |B |C |

| |Ms. C |12 |24 |12 |

|Teacher | | | | |

| |Mr. M |6 |12 |18 |

| |Mr. W |15 |6 |3 |

(a) Determine if these teachers, as a group, meet the established standard of 30% A's, 40% B's, and 30% C's?

(b) Is there evidence that the grading patterns are associated with the teacher who awards the grades?

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