Tarea Estadistica 1y2

Chapter 1

Data and Statistics

4. a. The seven elements are the seven schools shown

b. 5 variables: State, Campus Setting, Endowment, Applicants Admitted, and NCAA Division

c. Categorical variables: State, Campus Setting, and NCAA Division

Quantitative variables: Endowment and Applicants Admitted

6. a. Quantitative

b. Categorical

c. Categorical

d. Quantitative

e. Categorical

10. a. Quantitative; ratio scale of measurement

b. Categorical; nominal scale of measurement

c. Categorical; ordinal scale of measurement since the responses can be ordered from earliest (high school) to latest (retirement)

d. Quantitative; ratio scale of measurement

e. Categorical; nominal scale of measurement

15. a. Quantitative – number of new drugs approved

b. Time series from 1996 to 2003

c. 18

d. 2002; 16 new drugs

e. Over the eight-year period, the number of new drugs approved by the FDA declined. From approximately 50 new drugs approved in 1996, the most recent years are showing only 16 to 18 new drugs approved.

24. a. This is a statistically correct descriptive statistic for the sample.

b. An incorrect generalization since the data was not collected for the entire population.

c. An acceptable statistical inference based on the use of the word “estimate.”

d. While this statement is true for the sample, it is not a justifiable conclusion for the entire population.

e. This statement is not statistically supportable. While it is true for the particular sample observed, it is entirely possible and even very likely that at least some students will be outside the 65 to 90 range of grades.

25. a. There are five variables: Exchange, Ticker Symbol, Market Cap, Price/Earnings Ratio and Gross Profit Margin.

b. Categorical variables: Exchange and Ticker Symbol

Quantitative variables: Market Cap, Price/Earnings Ratio, Gross Profit Margin

c. Exchange variable:

Exchange Frequency Percent Frequency

AMEX 5 (5/25) 20%

NYSE 3 (3/25) 12%

OTC 17 (17/25) 68%

25

d. Gross Profit Margin variable:

Gross Profit Margin Frequency

0.0 – 14.9 2

15.0 – 29.9 6

30.0 – 44.9 8

45.0 – 59.9 6

60.0 – 74.9 3

e. Sum the Price/Earnings Ratio data for all 25 companies.

Sum = 505.4

Average Price/Earnings Ratio = Sum/25 = 505.4/25 = 20.2

Chapter 2

Descriptive Statistics: Tabular and Graphical Presentations

5. a.

Name Frequency Relative Frequency Percent Frequency

Brown 7 .14 14%

Davis 6 .12 12%

Johnson 10 .20 20%

Jones 7 .14 14%

Smith 12 .24 24%

Williams 8 .16 16%

50 1.00

b.

c. Brown .14 x 360 = 50.4

Davis .12 x 360 = 43.2

Johnson .20 x 360 = 72.0

Jones .14 x 360 = 50.4

Smith .24 x 360 = 86.4

Williams .16 x 360 = 57.6

d. Most common: Smith, Johnson and Williams

10. a.

Rating Frequency

Excellent 20

Good 101

Fair 528

Bad 244

Terrible 122

Total 1015

b.

Rating Percent Frequency

Excellent 2

Good 10

Fair 52

Bad 24

Terrible 12

Total 100

c.

d. 24% + 12% = 36% of adults in the United Sates think the Federal Bank is doing a bad or a terrible job in handling the credit problems. Only 10% + 2% = 12% think the Federal Bank is doing a good or excellent job.

e. 40% + 10% = 50% of adults in Spain think the European Central Bank is doing a bad or terrible job in handling the credit problems. Only 4% of adults in Spain think the European Central Bank is doing a good or excellent job.

Both countries show pessimism and relatively low confidence in how the banks are handling the credit problems in the financial markets. But in comparing the two countries, adults in Spain show more concern and more pessimism about the bank’s ability compared to adults in the United States.

17. a. The highest price stock is for IBM with a price of $107 per share.

The lowest price stock is for Alcoa with a price of $11 per share.

b. A class size of 10 results in 10 classes.

Price per Share Frequency

$10-19 5

$20-29 10

$30-39 3

$40-49 2

$50-59 6

$60-69 2

$70-79 1

$80-89 0

$90-99 0

$100-109 1

c.

The general shape of the distribution is skewed to the right. Half of the companies (15) have a price per share less than $30. A mid-priced stock appears to be in the $30 to $49 range, while the most frequently priced stock is in the $20 to $29 range.

Five stocks are less than $20 per share (Alcoa, Bank of America, General Electric, Intel and Pfizer).

Four stocks are $60 or more per share (3M, Chevron, ExxonMobil and IBM).

d. A variety of comparisons are possible depending upon when the study is done.

19. a/b/c/d.

Class

(Minutes)

Frequency Relative Frequency Cumulative Frequency Cumulative Relative Frequency

1-5 12 .60 12 .60

6-10 3 .15 15 .75

11-15 2 .10 17 .85

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