Estadística

1. A study about the behavior of the level of sales when it is modified the sales prince is been doing. In the table are shown the data:

Demand according to the Sales price

Sales price Level of price

75 7000

80 6000

90 4500

110 4100

130 3800

150 3000

165 2600

200 1000

Graph the information and calculate the regression equation that represents the data.

2. The amount of compact discs “CD” that have been produced in the period from 1985 to 1992 was recorded.

Production of compact discs

Year Produced CD

1985 5800

1986 23500

1987 51000

1988 102500

1989 149900

1990 205400

1991 288300

1992 333500

Graph the data and determine the regression equation that represents them.

3. An exam of verbal and numerical abilities to 8 students of the high school was applied, in order to determine if there exists or not an association between both abilities. The results are shown in the following table of data.

Punctuations in the selection exam

Student Verbal ability Numerical ability

1 250 280

2 280 300

3 300 300

4 310 400

5 350 350

6 400 530

7 450 400

8 480 480

Determine the regression equation that matches the verbal ability with the numerical ability.

4. In the last years a company has been done expenses in advertising, but t is unknown if this has some benefit for the company. Given the previous, it is decided to find out if it is possible that there exists or not some relationship between the expenses and the profits for the company.

When reviewing the reports of the company, it is found the following:

Year 2005 2006 2007 2008 2009

Expenses in advertising (thousands of pesos) 70 75 80 90 104

Profit (thousands of pesos) 330 450 500 650 670

Determine if there exists or not a relationship between the variables. If there exists a relationship, calculate an equation to represent the behavior between the expenses in advertising and the profit.

5. It is desired to determine an equation that represents the relationship within the distance that exist between the fan and the button on a computer and the number of errors that are presented in the switching-on. From the following information, solve a and b.

Distance Number of errors

1.0 65

1.5 52

1.8 48

1.9 50

2.2 50

2.5 45

2.7 51

3.0 32

3.5 40

3.6 50

3.8 35

4.2 40

4.5 20

4.5 30

5.0 25

5.5 20

6.5 10

a) Graph the information

b) Calculate an equation to represent the behavior

7. An experiment in the corn crop to determine the effect of the nitrogen in the efficiency. It was established four different doses of fertilizers (40, 80, 120 and 160 kg/ha) plus the witness (0kg/ha) and the efficiency was measured in kg of product by hectare.

The results are shown in the following table.

Kg of N/ha Performance

0 900

0 800

0 1100

40 1850

40 1990

40 2100

80 2800

80 2500

80 2600

120 4000

120 3800

120 4100

160 4200

160 4400

160 4150

a) In case that exists a relationship between the data, what would be the independent and dependent variable?

b) Graph the data

c) Determine a linear equation that represents the data.

7. After performing a series of experiments it has been determined that there is certain relationship between the

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